The rule of thumb is that a filesystem needs about a decade or so[0] to iron out the bugs and become reliable enough for regular use by regular users. Btrfs is

The rule of thumb is that a filesystem needs about a decade or so[0] to iron out the bugs and become reliable enough for regular use by regular users. Btrfs is 14 years old which means it's old enough to start getting adopted, but changing the default filesystem in a distro is not a particularly quick process, since most people simply don't care about most of the advanced features. Plus since data loss is such a feared problem, any anecdotes about it will cause a massive hit to the filesystem's reputation, regardless of the anecdote's validity. Right now Fedora and OpenSUSE use btrfs by default, likely because they're upstreams of enterprise distros where users will use those advanced features, so Red Hat and SUSE want to make sure it's as solid as possible before potentially rolling it out to paying customers. Personally, I'm a happy user of btrfs installed by default by Fedora and haven't had any problems with it, but I'm also not using any of the advanced features. [0] Source: casual conversation and poorly remembered anecdotes