I just (finally) looked up the features of Btrfs, and it sounds fantastic.  Possibly ZFS-adjacent but without the nightmarish license problems?  Am I missing something?  It's in the kernel, but if it was that good, lots of distros would be defaulting to it ... and they're not.  A couple have tried, but it hasn't taken off.  Can someone fill me in with the details I'm missing?

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