Wow, thanks for sharing. I remember having to avoid POW when writing shaders for a mobile game, just using ADD/SUB/MULT but my blends ended up being much more fiddly and hard to finesse. Nice technique.
tbh outside of Switch you probably don't have to worry at all about using pow() these days but it's worth second guessing whether you need to or not just in case you feel the need for a pat on the head from a render programmer. you could certainly insert a curve in place of the contrast function if that hit your visual…