I'm not too much of an expert on this area since I've personally tested this fork only with Smash Ultimate. I haven't had the chance to try it with other games, nor have I been able to check it out with the Controllers menu. That said, there wasn't any noticeable change with Smash loading times (no mods) in my experience, but unless someone does some in-depth testing, we won't know for sure. Sorry I can't really answer your question. I personally think that it shouldn't affect game loading times by much (if any), and that, without getting too technical, it should have no effect on anything other than the Controllers menu. However, this is only a guess based on what I know working with this project, which isn't an overwhelming amount.
I was actually thinking about implementing this. I'm busy with college right now, so I can't guarantee when I'll be able to get this done. I'm totally fine with it if someone manages to implement this before I do though.