If a user migrates from RHEL 7 to the next version of RHEL (or CentOS), there will be continuity in used algorithm and history db checksums. It's important to some enterprise customers to keep the history db in a good shape. Fedora users don't care about that much in general.
I care about maintaining dnf history in Fedora, it is a very useful debugging tool. Seems like it is broken in rawhide: https://bugzilla.redhat.com/show_bug.cgi?id=1598590 Is the hash reason why dnf 1/2 history doesn't work with dnf 3?