For no particular reason, except for btrfs taking up less RAM. I don’t know their specs, but the lack of RAM was my reason for deciding against btrfs for my large non-mirrored HDD.

I personally really like btrfs for my large media HDD because it makes copying large files an instantaneous operation.

Also, it’s useful to have 6 hourly snapshots in case *arr upgrades something or anything else happens (btrbk).

It’s not necessary almost any time, but the times I needed it a CoW FS with snapshots came in handy.

Edit: Also, btrfs does check summing, so it’s possible to detect bit rot.

Because YouTube pays Louis Rossmann, compared to selfhosting video which costs tremendous amounts of money through bandwidth.