Knowing that you might lose something during your attacks, I reckon many people would be more careful about how they move… and this could encourage new players to join, even those who aren’t part of an organised group
Losing crew would make far more sense than being rewarded with points while playing the defensive side.
That will also force your attacker into spending points, so losing them in some sense, because if they lost a battle and their crew got weaker, they will have to spend their points and rebuild the crew.