I'm assuming for role playing but other than that, how often do you visit your interior? I'm mean what do you do in there? I wouldn't mind having a accurate defiant bridge and interior for my defiant, but I don't want to spend $20 bucks to get it. I happily spent that much for the retrofit however, because well that's a whole ship.
Admittedly I don't visit my bridge super often but its fun from time to time to walk the halls of your ship (I have the TOS bridge so its fun to nerd out on).
Also it is handy for a quick meeting place - I can go to my bridge and toss out invites to people regardless of what sector they are in and they can immediately join me on the bridge - this comes in handy for a quick trade of credits or something if a fleet member needs help.
Only reason is to instantly trade with someone. Parties are better at DS9 or ESD or First City, the halls are far too large and ugly, your crew never wears your uniform, there's no reason other than to instantly meet someone for a trade.
The only time I visit my bridge is when a Mission requires me to. For example, the Reman FE had some segments requiring me to be on the bridge - and I went to the bridge to get into my Shuttle for 2800. There are several Foundry Missions which do as well, but that's about it for me.
Use to, you had to go to your ready room to replay a mission. I think that feature should be restored. I did use my bridge for a Role-playing conversation (the contents of which are priveliged). Besides braging rights, not much really does happen there.