I like relying on `git tags` even in continuous delivery situations. `git describe` is often good enough for continuous delivery versioning `v1.2.3-4-gabcdef` can describe a commit exactly enough to make git happy and is semver-like enough to set expectations, even/especially if new `git tags` are only ever inserted on human discretion (this is breaking change so I need to tag a new major now). The only real debate with `git describe` format version numbering is if to better conform to semver expectations the first dash should be a plus or not and you can do that change with a quick regex if you feel it is worth it for whatever is enforcing your semver expectations (ordering versions correctly in a package manager, for instance).

`git describe` is easy to automate for CD, but can leave version number decisions to people via `git tag` choices (and/or GitHub Releases) rather than trying to guess from commit history magic keywords.