I couldn't believe it either when I saw the proposal, so 2010-ish :)
Anyway I'm in great favour of this proposal and I'd love to see btrfs the
default.
I personally use it in all of my systems (desktops, laptops and workstations) except for
servers, where it lacks the reliability on some raid configurations I use (instead I use
zfs, which also supports native encryption).
I had my share of issues in the early days but it has proven to be extremely reliable
lately.
My biggest complain nowadays is this:
https://lwn.net/Articles/674865/
Not being able to mount partitions of my Raptor Talos Power 9 into my x86 systems annoys
me, but I guess it shouldn't bother many people. On the other side I had lots of
hardware issues on my Raptor machine and my btrfs hourly snapshots already saved my day
multiple times (latest one was while upgrading from Fedora 31 to 32). Would love to see it
the default, possibly with full grub rollback integration.