by doing so, it can result in a number of advantages: there is less/no blockage of the movement by other joints/structures, the nervous system can release muscles because it finally knows the joint is in a better place, etc.

the other technique you mention involves distracting joints away from their sockets. over some time, this can be because your muscles get tight around the joints, and they pull the joint into the socket for protection. over a long time, if it’s not addressed, it can/will result in degeneration of the structures within a socket and the joint itself. so distracting can help the muscles release around a joint/socket, as you mechanically provide more room for the joint to move. the CNS senses this and thus starts the process of relaxing muscles and readjusting structures that were formerly locking down the joint.

if i were you, i’d do “back in the socket” work every day to reverse the effects of our 21st century lifestyle. distractions can help accelerate that process.  

but then if your goal was some particular physical position (ie. deep squat), distractions will increase the effect of mobilizations which compared to doing them without distraction.  but certainly joints that are back in their proper position in the sockets will help you achieve these positions more optimally. you may discover that if you don’t work on putting joints back in their sockets, you will plateau out in achieving some position – once you start working on the socket, then you magically get that last bit of distance down to ass to heels, or hands all the wall above the head.