You get a nicer, significantly simpler interface. You don’t need any tricks. You don’t have to google how to work yourself out of a bad state, ever. And you get near-perfect git compatibility (ie you can use jj on a shared git repo, doing all the same things, and your teammates won’t know the difference).
I’ve wondered if there is a psychological thing here: someone who spent time memorizing all the git nonsense may have some pride in that (which is earned, certainly), that introduces some mental friction in walking away???
I don't mind other people using jj, but I simply don't feel a need to try it. There's nothing prideful about that, it's just pragmatism.
My advice is to try it. You should like it, if you're in the majority of folks to give it a sincere shot. If you don't like it, cool. But then my advice changes. jj is probably the future. Adapt or become one of those old-timers who froze their learning in time.