So, I do think that something like matches makes sense. I'm not suggesting we shouldn't do it. But we already have if let, and extending that to allow chaining would be an intuitive extension for people who are already used to if let; I think we should do that regardless. Then, we could define matches as a trivial desugaring, with if let taking care of details like the scopes of bindings.
I wouldn't want to have matches without having bindings, because it's incredibly useful to write things like if expr matches Some(x) && another_expr(x). That has all the same issues as if let, in terms of the scopes of the bindings. I think we should have both, and I think we should define the semantics only once.