It has nothing to do with immersion for me, there are other types of players than the 2 camps people want to seem to break it down into. I detailed in the post I made before my last why I don't think the introduction of this will be as big an issue as people are making out, before even seeing how it interacts with all the other elements of the game.
I don't have tons of money (and haven't actually played for months, though will play 1.3), but I have many times in the past been able to experiment freely with different load outs and also change stuff for single missions. I don't even have any of the really expensive ships that will lead to huge losses. I can still see it being a problem.
I really don't see what benefits this change brings. True, if it had been in from the beginning no one would have even noticed, but you could say the same amount real time mission timers...