The differences between the rules are not important, that's exactly why there needs to be a standard. TTRPG rules are not tabletop game rules: they don't say w

The differences between the rules are not important, that's exactly why there needs to be a standard. TTRPG rules are not tabletop game rules: they don't say what happens, GM does. TTRPG rules are a language that abstracts away trivia in a somewhat objective manner. This is similar to having many programming languages: ideally you would want to have a single language for everything, but they all suck in different small ways.