[ChrisNZ]

Chris, personally I do not see any merit in this exercise, but others may disagree.

I suffer from getting too flat in my backswing, with arms too across my body. I think when rehearsing right arm action, a bent elbow can fool you in terms of this, maybe because the right forearm feels relatively upright. If you take your backstroke with a straight right arm though, you can really feel if you are too flat at the top. Then with both hands on the grip you can look to duplicate the feeling (as Bucket explained, with a 'top aiming point'. That's the value of this for me.

Chris