It looks pretty normal to me as a professional Haskeller, though I suppose it's perhaps slightly cleaner to write it as conditionalBaptize p = fromMaybe p $ baptize p. It's largely just a matter of taste and I'd accept either version when reviewing an MR.

Edit: I just thought of another version that actually is far too clever and shouldn't be used:

conditionalBaptize = ap fromMaybe baptize, making use of the monad instance for ->. But yeah, don't do this.