The main benefits to BTRFS over something like ext4 tends to be considered as; the subvolume support - which is what’s used for snapshotting, the granluar quotas, reflinks, transparent compression, and the fact that basically all filesystem operations can be performed online.

I’m personally running BTRFS in a couple of places; NAS, laptop, and desktops. Mainly for the support to do things like snapshots and subvolumes, but I also make heavy use of both reflinks and compression, and I’ve also made use of online filesystem actions quite a few times.

Using btrfs makes a lot if sense on a NAS, because it allows you to make snapshots in a nice way. It also has some features that give your data better odds of survival if something goes wrong.

For a data disk? Absolutely, even if you’re not going to configure anything, you can copy inside the partition instantly and detect the bitrot.
If you’re willing to step it up a notch, there’s also cool stuff like transparent compression, deduplication and incremental send/receive of entire subvolumes.

non system disk

That really depends on what you mean by that? Is it an internal or external drive, what sort of drive is it (HDD, SSD etc), and what are you going to use it for, and are you planning to share the drive with other operating systems?

Because while btrfs is nice in general, you may find other filesystems more suitable, depending on your usage requirements.

I usually just stick to the standard file system to any OS.

So for Linux that would be ext4.

For external drives i use either FAT32 (the ol’ reliable) or exFAT (the fastest for dealing with large files when you set the max allocation unit size AKA 32MB).