So the mate in X exercises are basically like a bunch of trick shots in pool requiring pieces to be in a bunch of incredibly arbitrary positions that apply only to that situation and would never occur in real life and are completely useless in practice because you'd never be able to get in that position to begin with. That's hardly going to teach me to be a more advanced player. And it's not an advanced player who would consider playing blindfolded chess, just an insane one with no valid purpose for existing, to memorize and drill with that.
But it's a unique and mildly interesting little flash file anyway.