As someone pointed out on Reddit:
I think the reason they need instant ship transfer is to do with upcoming multi crew (in 2.3).
Think about it... your friend meets you in the station, you transfer to his ship leaving your ship behind.
You guys are now both in his ship.
He flies across to somewhere else stops at a different station and realises he needs to log off to go to sleep. You are now stuck. Realistic = Yes .. Fun = No.
So having instant ship transfers mean you can resume play.