OK, I have been working with it and have achieved a moderate amount of success. Here is the point not taken into consideration. Generally we use capos with open chord forms played in first position. We don't need to, but that is kinda instilled in many guitaritst.

But if you allow alternate chord shapes and non-open chords than this does indeed work as it claims. Actually, it has been insightful. My song in C needes to go down to Bb. Normally to maintain the exact open chord shapes these means Capo 10 - not always the best (and a problem since BIAB changes the chords and it should not). With capo 10 it swiches to a D shape which means I am playing back in C. No good.

But if you experiment with capo 1 and allow the chords to change (permitting non open chords) well that does it. All in all a little tricky but interesting.

Capos, like any alternate tuning, can really mess with you mind. And that chantge in chords for Capo 10 is just not right.