Well, that's partly disappointing, partly good news - Good news in that we don't have to waste valuable move slots for these, but it's disappointing because I don't like the thought of being forced to use a very specific Pokemon for a specific goal. It's even more limiting than the HMs, IMO. I don't like the thought of having no choice in which Pokemon I get to ride in the overworld.
I mean with surf it always just some generic looking pokemon stand in, so not sure how it's any worse.