When I first saw this pose, I thought the one behind needs more strength to support the partner in front. But in fact, the one stepping on top is not entirely resting. I used a lot of strength from arms and shoulders (trapezius muscles) to support my body weight. What I thought was, it's a good practice for handstand. Practicing against the wall seems the same, but to me, the wall is too comfortable to be leaned against to, a human partner on the other hand, gives me a feeling that I'm becoming the burden, I shall stand on my own (hands).
And what reminds me of this pose is: I love my 2 dogs! Now, feels just like having a new-born baby at home, always rushing home after work to see them.