In Steam, it is possible to create profiles for non Xbox and PS controllers, but in my experience, the process is needlessly coercive and confusing. Like, if I plug in an N64-to-USB controller, and go into Steam, a menu navigation layout will automatically be imposed on the controller. Supposedly, this is meant to be a nice thing - after all, if you have menu navigation automatically imposed, that means you don't have to use a mouse and keyboard, and it is true that I don't like using a keyboard in a living room. The problem is, you have to play trial-and-error to figure out what layout Steam imposed, and it also means you have to create a layout for the controller, while some other layout is already active, and to me, that's incredibly confusing.
If you do find Steam's custom setup process easier than JoyToKey's, I think that anecdote is reasonable, although I believe that Steam has gotten gamers used to thinking that keyboards, mice, and ordinary Xbox controllers are the only peripherals that PC gaming really needs, which is a conclusion I resent.
For the last few years, I've been working on a Steam alternative, which uses JoyToKey as its foundation, and that's one of the reasons I'm chatting with a lot of developers right now, trying to see how they react to my emphasis on JoyToKey-friendliness.