That works perfectly well with semver, e.g. Cargo interprets `foo = "42"` as implying a constraint of ^42.0.0 (https://doc.rust-lang.org/cargo/reference/specifying-depende...)

In the meantime, semver is good because it gives us a small number of additional semantics to impose on version numbers if we wish. Semver is not a solution to versioning, it's just a foundation to build better automatic versioning tools atop of, such as the tool linked here.