Yeah, I wonder why Rust needs to have statements at all--why can't it just have "everything is an expression" semantics? Why aren't declaration statements in R

Yeah, I wonder why Rust needs to have statements at all--why can't it just have "everything is an expression" semantics? Why aren't declaration statements in Rust just expressions that evaluate to the value being bound to the name being declared? Would this mess up Rust's type checker somehow?