I think that's harsh. Yes there have been past problems, but for some scenarios it's amazing.
I believe there are still issues around metadata safety/reliability with raid5, but that's not to say you can't use raid5 for your data (mkfs.btrfs -m raid1 -d raid5). I know there were some curious scenarios in the past like a 2-disk raid1 would not mount if one of the disks was missing or failed. That would worry me especially when you're too busy to have to figure out and learn about 'why won't it work with one disk.. it's a two disk mirror ffs, that's the whole point'. Don't think that's an issue anymore. Last time I looked at quotas they killed my performance, and I was only enabling them to try to get a clear view of snapshot space utilisation.
I think if you consider the plusses: snapshots work well, compression works well (zstd:2 a big win), the multi disk stuff is super flexible and impressive (and the whole concept of how it deals with multi-disks and errors/failures) and the send/recv stuff, and then maybe put the deduplication and quotas into the 'not quite sure' category.. well, you still end up with a pretty awesome thing. That's where I'm at anyway.
I've given it some abuse over the last few years and I'm doing ok I think. I ran it atop an md-raid0 for a few years, and now have the above btrfs-raid5 with raid1 metadata. This is for storing backups of Windows servers and esxi boxes. The btrfs snapshots work well for Windows wbadmin since it appends to the same vhdx file each time. Not so well for esxi ghettovcb since they're not incremental. I use snapper. Being read-only snapshots by default is good from a ransomware protection perspective (in case the server doing the wbadmin backups is compromised).
Being on Fedora is nice because it's pretty much bleeding edge with the kernel and btrfs utils etc.
Obviously you probably all already know that Netgear (for easily more than 5 years) and Synology (maybe more recently?) Use btrfs on their NAS boxes for snapshots, usually on top of their own (or probably a tweaked md) multi disk raid type thing.