The ship based combat criticals are super nasty. "Hull breech, lose 5 crew".
FP are a mechanic that has more to do with making your game more cinematic/heroic, so I don't think the genre of the game matters so much as the flavor you want.
Indiana Jones and Han Solo both seem to have used a lot of them, as do most cinematic heroes.
For a one off game intended to be played in one session, 2 may be the limit, it might even be a bit too many, but in my experience, there are players who fritter them off for nothing, and others who will never ever spend that last FP except to save their character's life, so giving two might inspire the bankers to actually spend 1 for something less dire than death.
Basically, if the intention is for them to be used only to stay death, give 1, if you also are OK with using them to re roll a plot-centric roll, then giving 2 works.