There’s been some Friday night kernel drama on the Linux kernel mailing list… Linus Torvalds has expressed regrets for merging the Bcachefs file-system and an ensuing back-and-forth between the file-system maintainer.
This is actually a feature that enterprise SAN solutions have had for a while, being able choose your level of redundancy & performance at a file level is extremely useful for minimising downtime and not replicating ephemeral data.
Most filesystem features are not for the average user who has their data replicated in a cloud service; they’re for businesses where this flexibility saves a lot of money.