pretty obvious.

if i have a spell that requires touch to cast. and use my fist to hit them, can i also cast that spell since I'm touching them?

i mean it seems logically i could.

is there anything saying i can't? i think it would be a real benefit.

It would seem to me that you could, that being said I feel like it would be fair to require that the zeon already be accumulated by the time you launch the attack. And of course there would probably be penalties of some sort though I can't exactly pull out my books right now to check on that. The way I see it if I were to simply try to reach out and touch you against your will you could dodge it, and that isn't too different from a normal attack when you look at it.