Going to tell it like it is.
STO is an easy game.
Elite STFs are easy.
If a group fails at an elite STF, it's not because someone is using rainbow beams.
Elite STF failures are caused by poor play (e.g., not enough DPS in-time, spending long periods dead due to not avoiding hazards, etc), failure to coordinate and focus fire, failing at objectives (destroying gateways/cubes in the wrong order)...but they are NOT caused because some people have something like 10% less base damage than they might have, because they use rainbow beams.
STO is easy, and as such, it attracts more than its share of false elitists.
False elitists pride themselves on measures of merit so shallow and stereotyped as to be meaningless. Like thinking they're pro because they know not to use rainbow beams. Knowing not to use rainbow beams, something that most false elitists know only because they hear what is really a sort of meme endlessly parroted by others, does not make a false elitist elite.
The very fact that these false elitists bawl and bawl about baddies with rainbow beams, as if there's nothing else that plays into the skill equation - let alone far greater factors - proves that these false elitists, so far from being elite, are truly terrible players who do not understand the nature of real skill.
Very few truly skilled players play STO. Most skilled players play more competitive games like EvE and SC2, or even high-end WoW PvP/PvE. Because of its low skill cap and paucity of genuinely challenging content, STO is necessarily a very casual game, albeit one that reflects the realities of the MMO community where "casual" is often conflated with "hardcore bad"...and so we have the false elitists, who can't cut it anywhere else.
If a player does not yet have (or does not care to invest his resources in) an entire setup of high-level beams and dedicated consoles, and instead just uses whatever are the best weapons available to him, or is simply a "Handsome Boy" who really loves "Rainbow Power", that's perfectly fine. You don't have to invite him to your fleet, and he's not going to be more of a liability than the idiots who loudly cry in teamchat about rainbow beam baddies while themselves failing to play to their full potential in the more subjective ways that actually matter.
So no, OP, it doesn't matter. What you are hearing is nothing more than the wails of frustrated false elitists.
True elitists are elite - skilled and experienced gamers who can play any game extremely well.
What makes the "elite" a "true elitist" is that they understand and recognize skill, and associate with like-minded people. They aren't the ones doing randoms and crying that some other random is running rainbow beams.
True elitists understand the nature of skill as fundamentally based on experience, self-discipline and execution, and they've been around the block enough times to not get hung up over a marginal game mechanic that doesn't matter nearly as much as other factors and isn't why the team wins or loses.
I don't claim to be elite, I simply have enough experience and understanding to know why rainbow beams just aren't a big deal, and what motivates the kinds of players who fixate on them.
The "elite" in "elite STFs" is just a marketing ploy. There's nothing "elite" about them. They're marginally more difficult than normals but they are still not so tightly tuned that min-maxxing is necessary to succeed nor more important than other factors such as teamwork and execution.
The difference between a general beam array tactical console and a specific console, at max level, is 8%. Which doesn't sound much, but then say you have 3 consoles (assault cruiser, say), that's 24% less base damage. This is like deciding to give up 6 weapon power (as in somehow magically throw it away with no benefit) to look pretty in combat. Consider a weapon power console is +3 or so weapon power. So, in a sense, you are giving up two console slots or credible weapon power because it amuses you to shoot rainbows. I mean, I'm sure you could get some pve done with Common shields/engines/deflectors/weapons, too. Go nuts. But there's no reason to do this intentionally on a team other than ignorance, stubbornness, or because you like griefing folks. May as well show up in a shuttle, that'd REALLY be funny, huh?
...isn't there DR on consoles?
None of which matters a damn because it will not cause you to fail.
At worst, the suboptimal configuration will cause your 15-minute STF to take one more minute than it normally would.
And if that minute caused you to fail the optional...then you shouldn't have queued with randoms trying to get it in the first place...besides, no doubt there were other, more significant, factors in play, causing you to fail it. Mobility/coordination/teamwork issues, whatever. All of which individually cost you a lot more than that one minute.
So if it doesn't really make a difference, besides, at most, one minute of your precious little life...why do you care?
And it may very well cause you to fail, particularly in Elites -- if you are defending and don't manage to do quite enough damage fast enough, you could get swamped, a target could get destroyed, etc.
Last night I failed the Cure Elite optional because I didn't quite get over to the BoPs in time and Kang hit 74% hull (74%!! Missed it by _one percent_, dang it). Now, I could have better weapons, and my consoles aren't maxed out (because I can't yet afford it).
If I had been able to do a little more damage, we would have gotten the optional.
If I had mixed energy types and general energy consoles, ... yeah, that would have been terrible, and probably the rest of the team would have to constantly stop to help me, and Kang might end up destroyed outright (though probably they would have told me to stop guarding because I'm useless).
I mean, consider a cruiser deciding to only slot 6 weapons because he likes the number 6. He MIGHT get the job done but he's handicapping himself for no particular reason.
There's NO REASON to handicap yourself, and it's not onerous to just pick one energy type.