I can't say that I like using tenfa like this. It seems to me like a happy coincidence that we use exponentiation notation for both repeated multiplication and repeated function application in general.
I also don't like allowing both numbers and predicates in the tenfa, if we were to try generalizing it without adding a place for the predicate (in which case we pretty much wind up with my predicate, but with the possibility of non-natural exponents, which doesn't make a lot of sense outside of exponentiation.)