Not sure it is helpful/sincere as both players will be influenced by the other's thought processes rather than the moves on the board. The weaker player would gravitate towards "trusting" the other's analysis/evaluations.
I'd much prefer that both sides "write" their thoughts and share them in the post-mortem. That allows for no interference/distortion when you compare their plans/thought processes.
Any opinions on the technique of playing an opponent while you both voice your plans out loud? Are there any trainers here that use this between themselves and their students, or with 2 students of roughly equal strength playing each other?