The white doffs are generally good for 4 things:
1) Filling your doff roster for the very first time
2) Dismissing them for dilithium and Recruitment XP
3) Using them for contributions in the starbase.
4) Using them to get higher tier doffs
Now after the patch the fleet doffs would not be useful for 2 out of those 4 things.
Now that makes them pretty much useless.
I can understand Blues and Purples, and up to a point Greens, but White Doffs that can't be contributed are plain useless.
I haven't checked if they can be used in the grinder, but if they can, their only possible usage is to give 5 for a green and then get back 3 from the very same green.
I would also want to hear an explanation to what is intended to accomplish with those new doffs. (Even though the most probable answer is the one we fear most: Just for the starbase to have some fluff and something for us to spend our money on)