Btrfs is the default on a few systems already like Fedora, suse, Garuda, easynas, rockstor, and some others. It's not the default in Ubuntu and Debian, but I wouldn't say it didn't go anywhere either.
The only thing to be aware of is to disable CoW/Hashing on database stores or streaming download folders. Otherwise it'll rehash each file update, which isn't needed.
The real issue is that modifying large files on a COW filesystem causes it to spread that file's guts all over the disk (i.e. fragmentation), and results in serious performance loss over time.
For some reason that doesn't happen nearly as much on ZFS and it's totally fine for VM and database workloads.