Although wasps/hornets aren't as efficient as bees at pollination due to their bodies not being as hairy as a bee, they do still play a part. If we were to eradicate all wasps/hornets it would cause more problems than it would solve.

Seagulls on the other hand, do not have one redeeming feature in my opinion. I'd be happy to see them wiped off the face of the earth...humanely of course. Noisy, screeching, squawking, filthy, avaricious, dangerous, and aggressive. But I suppose members of the RSPB wouldn't agree with me.