[dogscoff]

Satellites cannot be trained unless you are lucky enough to have a planet sitting on the wormhole or unless you have system wide fleet training facilities

Actually, satellites can't be trained at all. Nor can fighters or drones.

Missile sats are often worthwhile, especially in Proportions. Combine them with fighter defences to help overwhelm enemy PD.

I build lots of sats: As has been pointed out before- they cost no maintenance and (once launched) no cargo space, so if your storage is maxed out and you have resources going to waste and you have a spare build queue then there's no reason whatsoever not to build them. Even if they don't hit anything, at the very least they will soak up a few rounds of enemy fire.