It's only an alternative if you have a backing swap device. zram does not have this requirement, so (aside from using no compression) it's basically the only solution for some scenarios (e.g. using entire disk(s) for ZFS).

Can't you use a ramdisk as your backing swap device?

Using a ramdisk for zswap is basically just zram with extra steps.

It is not the same at all. The swapping algorithm can make a big difference in performance, for better or worse depending on workload

Zram is just swap but in RAM. It uses the same algorithms as normal swap

Extra steps are fine if the result works better.

If you use hibernation, I think it also compresses your RAM image for potentially less wear and faster loading/saving

why hibernation would not compress to begin with? you're more likely just end up running zstd twice.

Swap isn't compressed by default, hibernation dumps memory to swap

Hibernation uses compression regardless of zswap

Thanks for the correction