A) only valid if you want to stay with the devel version
B) See A
I use OpenBSD and before that, I was on alpine, debian, and arch. Of it was a software I want to try, I downloaded the tarball. if it’s something I wanted to keep for longer, I created a port or a custom packages.
You should invert your framing.
It's only *not valid* if you intend to use a fixed version forever. Otherwise you might as well include versioning for any other case.
Of course it's valid for release versions too: just fetch and checkout the release tag you want. I do this all the time.
Juggling multiple directories and tarballs is a pastime from a bygone era. It's even more commands if you want to reuse the existing directory!