I'm using one on my 5.56 build so if need be I can shoot the lower pressure tula ammo.
I'm using one on my 7.62x39 pistol build to regulate recoil, because a lot of the hellpups suffered either over gassing or under gassing.
Other then that only if you plan on using rifle grenades, or are ocd, no practical reason to offset the cost on a standard ak build.
The only ones available are the Dez Arms, they are really ugly boxy looking, Impossible to find used, Dez is out of stock on them, they sell for $100 + shipping from them, I'm still trying to find a couple myself, there was a guy on one of the boards converting Yugo m70 grenade gas blocks, but I'm not sure about the journal size fitting a .590 barrel?