[DS] Doesn't make any sense

I've reread all the rules multiple times, and this still
doesn't make any sense.

VTOLs may have 1 class one weapon in a turret.	Everything
else has to be fixed mount.

Fixed mount weapons may only be fired before movement.

Why would I ever do a pop-up?  I can only fire a single
class 1, much danger for  little affect.

The only real use I can see for attack VTOLs, as I
am currently seeing them, is hanging them out waiting
for opportunity fire.  Of course if they use opportunity
fire it is an invitation to die since they can't move
and they are lightly armoured.

How the heck do you use an Attack VTOL in DS?