I think maybe you think I said "zram offers a subset of features of swap space". Rather, zram offers a fundamentally different function from swap space as it resides in memory rather than on disk. It does not and cannot replace the function of disk-based swap space.

Edit: again, I don't want to argue semantics, generally when people say "swap space" they mean the on-disk partition and not just any memory that can be spilled to.

TIL that zram actually does advertise itself as somewhere you can swap to, and generally their terminology is correct, but I think most Linux users colloquially understand swap space as residing in nonvolatile memory.