It depends on what you call "real" data.

I find it good enough for home NAS that serve as jellyfin instance and store a hell lot of stuff. Things I would rather keep, but anything really critical is stored on several computers.

Works well so far (about 4 or 5 years already now) with raid5 for data but raid1 for metadata.

it's still unstable and shouldn't be used for anything except testing

Given how flexible RAID1 in btrfs is, I don't really see any benefit in using RAID5/6.

I tried it probably a decade ago and it ended badly.

The last time I checked it seemed like "the powers that be" running btrfs had shifted focus away from raid 5/6 because enterprises didn't care about it.

Fragile. Works great when its working. When thjngs go wrong it’s difficult to see how anything can be salvaged.

If the devs say "unstable", it's probably unstable.

I use it on my laptop and haven't had any issues

Some people in the comments of this claims to use it with real data https://www.phoronix.com/news/Linux-6.2-Btrfs-EXT4

If you use it don't forget to use RAID1 for metadata

Yes.