> Both result in multiple states of the same identifier, so I don't quite see the big difference here.

Shadowing is something you can figure out purely on the syntactic level.

Figuring out mutable state requires solving the halting problem.

> Fair point, though in that case I'd be more comfortable separating those variables into scopes.

Well, they effectively have different scopes. The scope is just not delimited with curly braces.

It's similar to how eg Haskell's variable binding in do-notation extent to the rest of the do-block. Each line introduces a new scope.

However, I can re-interpret your comment as saying that you want a more explicit syntactic marker for a new scope. And that's a fair enough request.