Yeah I thought of that way too, xstate is just fabulous. But I believe statecharts could be more widely used in both clj & cljs so I decided to roll my own. Still lots of the API design is borrowed from or inspired by xstate.
Here is an excellent article about making use of the parallel states features (and other features) of clj-statecharts: https://doughamil.github.io/gamedev/2021/03/24/statecharts-for-animation.html .