Losing crew is technically no different to losing any other required resource.
Technically because you can't replenish it in the field, unlike supplies and fuel.
Fighting against large fleets is
significantly easier and quicker when you have a force multiplier in play, such as fighters.
And large fleets are an excellent source of both supplies and fuel.
You are guaranteed to lose crew doing this, which is has the potential to put your fleet under it's CR threshold and render ships non-viable for combat, which in turn requires eventually abandoning whatever you were doing to fetch more crew as you can no longer use combat to recover fleet resources.
Mitigating fighter crew losses is a very useful ability for me because
fighters are the key to turning hostiles into useable resources with the minimum fuss
Drones mostly remove the need for this. But you
have to do this in order to get them. And you'll probably want to keep manned bombers anyway because they're just better.
You might not care about this because you have a different way of doing things.
And that's fine because sandbox.