Hello,
Well, first of all, it's a question not an assumption so please don't shoot
Instead of creating the "RAID5" the proper way via and mksf.btrfs command to get the benefits of BTRFS + RAID5/6 (which is not recommended), is there any benefit from creating a RAID5/6 via mdadm and THEN formatting it using mkfs.btrfs as if it was a "single" BTRFS volume (and leave the RAID5/6 stuff to mdadm) ?
I mean, it can't be worse than just formatting the an mdadm array as ext4, there must be some benefit in formatting as a single btrfs volume.