The new scheme is fine. They are correct to describe it as semver-compatible — they assess that every time they add functionality it is backwards-incompatible, and their backwards-compatible changes are inherently just bugfixes. And they are correct that Firefox version numbers have been doing the same thing, and thus their way is not unique.

The old cryptography version numbers were not "floating point numbers" (as demonstrated by the fact that they often had two decimal points). They were just incorrectly using the major and minor parts of a version number to communicate what changed between releases. They weren't doing anything like expecting version 1.11 to be treated as older than version 1.2. I can't fathom how this is supposed to have broken CI pipelines.

This is 100% classic perl: the default is bonkers and unintuitive, but the behaviour also changes in a DWIM manner to throw people off. And of course there are two different ways to represent versions so simply forgetting the v (one character) can cause a litany of bugs.