Since the reactivity api is exposed it's very easy to write a file to hold whatever state you want.

Benefits: easy to create, type safety is simple.

Drawbacks: you don't get a serializable state log for free (that can be recorded and replayed when hitting bugs).

Not sure about Vue 3, but in Vue 2 you can simply use a Vue instance without a template as a reactive store. You can also share an object between Vue instances.

See: https://vuejs.org/v2/guide/state-management.html

It's funny I still have never really understood the case for Vuex. So far I have built decent complexity apps just by having a global reactive object that all components link to directly in their Vue data and I have yet to hit a problem. I see huge writeups and design patterns all suggesting I really need to use a state management library and I'm waiting for the day the penny drops and I realise what a mistake I've made but so far everything just keeps rocking along .... what am I missing?

(I get that there are some nice features like time travel debugging etc but none of them seem outweigh the giant additional complexity of routing every single state change through 1-2 extra layers.)