It does a whole lot, on a technical level.
It would make the concept of stop releases obsolete.
Nope, I denoted is simply what “stop releases” always were.
… on an upgrade path, or your SailfishOS installation will likely be harmed: This is exactly what I wrote! Maybe no so “wrong”.
What you seem to be confusing (and I see Jolla’s documentation is contributing to it) is a release (a.b.c) and a minor update to a release (“point release”, which increases the micro version number).
But nevermind, usually one will upgrading to the latest versions of each stop release anyway, but in general there is no technical necessity for that.