relying on the fact that HIGH is 1 and LOW is 0, and that will probably never change
It's true, Dominik, one could do that. And it would probably
not cause problems in the future.
But, for me, probably isn't good enough. I've developed a number of habits over the years based on shortcuts just not being worth the trouble. One of these is never to assume that a macro won't change; I won't rely on anything other than the contract a macro implies. I have seen numerous problems caused by doing otherwise.
In this case, I actually the like the result of this habit; the code says "if the input is high, insert a 1, otherwise insert a 0." It's nicely self-documenting, and I like that, especially in code I write for somebody new to the environment.