Over the years I've seen several employers not archive object code, binary packages, etc. based on thinking that they can always be recreated from a saved source tarball, or source control.  That has almost always been a mistake, as by the time there was some need to recreate it, the tools had changed enough that it was actually quite difficult, even if the tools are also in source control.

The archival needs to comply with the GPL are different than the archival needs of a commercial (non-GPL) vendor, so the described problem isn't as relevant, but IMHO it's worthwhile to save the SRPMs and binary RPMs of released packages (including released updates), but not other koji builds.