I figured that out when I used the simulator to pit a group of my missile ships w/4 PDC Vs vs an equal number of missile ships. Was rather amusing.
Still, missiles might be useful if combined with other weapons, especially fighters. You can use the missiles to set off the point defense cannons in range and then send your fighters in unopposed. (Otherwise, you have to send one fighter group in to decoy all PD fire. Wild Weasels
)
Hmm... maybe an ECM mod for missiles using the Component Enhancement rules will be possible.
I guess I'll add that to the list of "things to suggest" for Component Enhancement. Already suggested adjusting reload times so you can make a rapid-fire mount or something that fires slower for various reasons. Giving a seeker an ECM rating might be possible.