There wasn't any discussion that I know of. I do not consider Carpalx to be one of the "good" layouts -- Colemak, Arensito, Maltron, etc. The BULP layout is pretty good, but it has problems. Travel distance is pretty good, though not as good as Colemak. It puts too much work on the right index finger (23%), and only 3% on the right pinky. Also S is not on the home keys, and it is one of the 8 most common keys. Same hand is about the same as Colemak.

The main thing that makes it not very good is the same finger. It has three times the same finger as Dvorak and EIGHT TIMES the same finger as Colemak.

Without even testing it, I can tell that QYLDG is worse. It puts A and E on the index fingers, leading to huge amounts of same finger. HA and AM are both very common digraphs. Also it puts semicolon on the home row. That is bad.

I am curious as to why Shai put it on the alternative layouts list above everything except Dvorak. Is it because it's easily available? (Dvorak is at the top because it's a "practical alternative".)

Edited for grammar.