No strong opinion here, but I see calver as a good fit for a new / rapidly changing project (with yyyymmdd being a both version and snapshot date), or for a software where you don't need semver guarantees about api change - so not for a library or for some important tool that is often scripted.

Or, as described in the project, calver might be good as a release date for a "umbrella projects" - like Ubuntu, or even Windows 10 builds.