The reason why it is useful to have it in the filename (together with
the
distribution tag) is that every output that concerns packages show the
package name. And it allows to identify immediately where it came from and
what it was build for.
It may not have been the purpose of the release-tag, but it's useful to
many (instead of silly). It wouldn't even matter if RPM had a special
extra tag after the release tag specially for this because it would act
exactly the same anyway (and would require change to all tools to be able
to show it).
the release-tag is considered in dependency resolution and version
comparison - I think removing all 'brands' from dep resolution and
version comparison is much more fair.
-sv