They are explicitly a beta channel, and in fact if you create a world on a snapshot you don't have an upgrade path to future releases (unless you start hacking at your world files with an NBT editor). So most of the community ignores them and waits till release.
Snapshots do let you upgrade worlds to future releases and you don't need to do any NBT editing, just upgrade the game and load the world.
Huh, I guess I assumed that based on the behavior of most of the experimental flags offered on world creation. Has that always been the case?
I think mojang is taking a turn away from experimental feature flags these days, so I guess this situation will get better over time.
Though there are of course no guarantees there won’t be problems with the world.