If you bail from a vehicle - the opponent will always get the damage points done to it as VP, which could be 1 point for a de-tracking.
But if the wandering crew are suddenly made dead, the vehicle is now considered fully destroyed for any VP purposes at game end. And for campaign core crew, they are going to be replaced with a less experienced newbie next battle.
If the crew are wandering about away from the damaged AFV, and an enemy occupies the same hex as the damaged unit, it is destroyed. Crew is then irrelevant (nil points), so if killed, it is only of consequence as regards campaign progress (it will become a newbie) - or for the killing unit as a kill point (aids experience gain), if it is itself core. Or, for any suppression to neighbours that its destruction adds. Or, if it is the formation leader, of course.
If you are thoroughly defeated (not a draw), any vehicles (and other crewed items like arty) with surviving crews away, even if alive - at end of game are considered dead for VP assignment, and are marked as destroyed. Even if only 1 point as a track hit. This is not the case for the winner, as he is considered to control the battlefield and so easier repair of wrecks on it. Recombining a damaged AFV or gun may be a good idea if you can,
if you are likely to be marginally or totally defeated - or they will be considered lost to the enemy as he will have battlefield control. Always providing that those units are in somewhere reasonably safe to do so of course!.
Basically - the crew
is the damaged AFV/gun, and so using bailed M1 (say) crew once rallied for "cheap expendable" scouts - is a
false economy
.
Cheers
Andy