Thanks for playing!
Yeah, the intended audience is mostly for those who are looking for something more after Sekiro, which is admittedly pretty niche.
1-4 is more in line with style switching like in the DMC games, and the advantage of this approach is that every ability is at most 2 inputs away, with the currently equipped ability only being a single button press rather than something like R2+X. It also allows for much more complex use of each individual slot, although this really only gets used to its full extent with the iai stance.