Not that useful, you're a LOT better off just running Aura Sphere and ditching Gravity altogether. With Focus Blast, you NEED to have Blissey go first, otherwise you start playing a very risky game. Since you can't guarantee that Blissey (or any Gravitymon, for that matter) will be sent out, set up Gravity, and be able to switch into Lucario to set up, you just end up risking your sweep with Focus Blast's lovely accuracy. Don't bother.No crap, but how useful might it be? Especially considering that Blissey and Lucario share a weakness and Lucario is switching is, soaking up an attack.