Honestly, it's not worth hording it. i doubt, what you have already collected will ever changed to unbound or bound per account.
I have some normal gear in my inventory which is bound to account, while another item of the same kind is still bound to character.
So, you have a small dilithium fortune there. use that. i havent calculaed exactly but that looks like more than 150,000 dilithium to me.
Those lowlevel ships are probably low level characters of Lieutenant level. Everyone gets bumped up to VA for those fleet event missions, that's why you didn't notice a difference, I guess.