And it's also integrated into the bootloader (if you use one of the supported ones). The bootloader shows you one boot entry per snapshot so you can boot an old snapshot directly.
I haven't tried it though so I don't know for sure. (I have my own custom systemd-boot setup that predates theirs, and since my setup uses signed UKIs and theirs doesn't, I don't care to switch to theirs. I can still switch snapshots manually with `btrfs subvol` anyway; it just might require a live CD in case the default snapshot doesn't boot.)
I'm using Tumbleweed with btrfs snapshots, systemd-boot and transparent disk encryption (using TPM + measured boot), works fine.
Currently this needs to be set up semi-manually (select some options in the installer, then run some commands after install), but it'll be automatic soon.
It is when the defaults make the parts integrate nicely like this that the “greater is more than the sum of its parts” come into place.