Primarily because it is more of guide to suit your personal preferences than it is a general purpose guide for other people.
There are also some style and practical issues. For example:
This whole thing could be rewritten as:
yay -Syu btrfs-assistant snap-pac-git snapper-tools snapper-support
It would be faster to install that way as well.
I don’t recommend using *-git packages unless absolutely needed because you are essentially testing development code in that case. For most people snap-pac is in the repos and will work for most people.
For most use cases, it should be sufficient to install either snapper-tools or btrfs-assistant since they have a tremendous amount of overlap.
I personally think it is better to set this up yourself instead of installing snapper-support. I don’t see much value in installing the custom path unit anymore and since we use dracut all the mkinitcpio stuff in there has no benefit
This is done already by snapper-support. Trying to do it again will just throw an error
Why would you do this as a manual command?
This snapshot will never be removed by snapper’s cleanup service so it will stay around forever unless you manually remove it later. In most cases, you don’t want that as it will consume increasingly more disk space as time passes.
Again, this may be your personal preference but removing the security on the snapshots subvolume isn’t something that should be part of the general advice for other people.
To be clear, I am not criticizing your process. I just think there is a difference between what should be in a “guide” vs how you personally choose to setup your system.