This depends on what you call "release" and what you call "devel".
I would say that "devel" implies new features, fixed bugs, but still some rough ends (e.g. docs not up to date yet). So it is a functional snapshot, announced only on the Kara-Moon forum.
OTOH, "release" implies everything is tested and integrated. Docs up-to-date. No known bugs. Announcements to all major sites and lists.
Alternatively, a bugfix-release is identical to the previous release with just one or more nasty bugs fixed.
I'm in favour of the "release early, release often" workflow. Looking forward to 19.08
.