In summary, the state of your state can be:
You can have local state to your component by just declaring it and using it locally to your component
There seems to be a trend where you would have to pick not only what tool you would prefer to use to manage your state, but also, that would constraint you on how to scope the state then.
The biggest use case for this, are the libraries that push for state to be always global.
We think that is a mistake, any modern web application has state and being able to choose the adequate scope for it is very important.