I love getting into the manned guns. They're absolutely the most convenient sortie ever. Pop in, shoot something, get killed or tower out. No flying back half a sector with missing parts only to crash in the grass & get a ditch/crash anyhow.
GVs are pretty convenient, since you can just shut the engine off & afk whenever you want; it's not nice to do that in the manned guns, since someone else could effectively be using them instead of you.
And I use them to peek on fields. I hate the whole annoying, change-field-use-the-arrow-key-to-push-yourself-out-of-the-tower-then-use-the-keypad-arrows-to-look-around. Just pop into the gun & use the hatswitch. It's far more convenient.