I think the parent comment is saying that, once I'm done prototyping with Fries, I'm going to move to native technologies, so I'll have to learn two systems tot

I think the parent comment is saying that, once I'm done prototyping with Fries, I'm going to move to native technologies, so I'll have to learn two systems total—and, since the parent comment asserts that prototyping in native technologies doesn't take too long, it wouldn't save me much time to use Fries, especially if I have to take the time to learn it.