No, a constant *can not change*. Whether a variable does or doesn't change doesn't make it a constant, just because it didn't happen to change. As I said, if you don't find value in it, don't worry about it.
Edit: it's also a matter of identifying the value. In a=b/60, what does 60 mean? If I have FPS=60; a=b/FPS, that has more meaning (assuming it's clear that FPS is frames-per-second). The named constant helps the next person who looks at the code to understand what is going on, rather than just having numbers scattered around.