Looks like a hack rather than a bit of sound engineering. From a mechanical perspective it might work for a bit but thermal cycling on that board-board mating will probably kill this dead. You need to make sure that both parts have the same coefficient of thermal expansion. That's a big problem with ceramic substrate BGAs already which have I think around a 5000 cycle lifespan to the point they are moving to plastic ones which are closer.

This succeeds in reducing reliability, nothing more.

I'm not saying these things shouldn't have replaceable SSDs for reference, just this is not the right solution.