Is spaceship armor useless?

[Ulzgoroth]

Originally Posted by vicky_molokh

I remember hearing that such attacks are defeated by something called 'whipple shield principle'.

Well sure, okay, but why do I have to invent systems and modifications from scratch to do it? Why is the TL11^ force shield totally wonderful compared to TL11 armour, but TL^ beams totally pointless compared to TL missiles? (There also isn't much of a serious reason to ever bother with bombs.)

TL^ is not a power level. TL^ beams exist to represent fictional beam weapons that don't act like anything really possible. They are probably mostly not drawn from settings where realistic kinetic-kill missiles are competing with them.

Originally Posted by vicky_molokh

Right now, anything short of an invulnerability field or indestructible armour is worse than having:
1. At least 11% as many missiles in a salvo as the target has PD guns and
2. The willingness to press 'Proximity Detonation'.
(Note: even if we postulated automated gunners that automagically hit with every shot for PD, then same has to apply to missiles.)

Have you forgotten about the rapid and very rapid fire options? A PD gun will almost certainly be VRF.