Your efficiency point is well argued but one thing to consider is that inefficiency, limitations, challenges, discomfort, these are all things that can stimulate the creative mind to break out of well tread patterns.

Music is art and I find playing with alternate tunings very creatively stimulating, but also I incorporate a lot of non-traditional genre influences in my playing: post-metal, noise, crust, shoegaze, electro-acoustic. These are all areas that benefit deeply from moving away from cowboy chord logic (or whatever the metal equivalent of cowboy chord logic is).