Not for everything -- so far, I've found it useful especially for Bach Prelude No. 2 in C Minor, WTC I, and also somewhat helpful for the Prelude No. 3 in C-Sharp Major, WTC I.
What you do is play the left hand part 2 octaves higher and the right hand part 2 octaves lower, so that the hands are crossed. You still play the left hand part with the left hand, and you still play the right hand part with the right hand, but you play them so that the right hand is on the left and the left hand is on the right.
It helped a lot with the C Minor prelude, because what it did is make the bass notes higher in pitch, and it is easier for the human ear to hear/understand higher pitches. So by practicing it this way, I heard the left hand part more clearly than the right hand part, and this helped me to work on clarity in the left hand.
Another benefit is that it helps to focus on the notes and on general clarity: because it "feels" different in this new position, and because it "sounds" different with the left hand higher than the right hand, one is forced not to rely simply on "finger memory" but to actually learn the right notes.
Of course it probably should not be a main practice technique that takes up 90% of practice time - just a small thing to do for a little bit after one can already play the piece as just one of several ways of helping to polish things up a bit.
