I have to say as an ex football player I would prefer the football helmet too. He had it in the car and we got it out and looked at it. The ball didn't fit through the opening and with a long QB mask it would protect as much of the neck as a hockey mask. You would have to worry about taking the mask off. Besides better vision IMO football helmets don't move around on your head (which is what I dislike about all types of baseball masks). Anyway none of us could think of a reason why not. So I mentioned I had access to quite a few baseball people and I would post the question to see their opinions on it.
So aside from a league or tournament rule. Why couldn't a kid use a football helmet for a catchers mask.