I bought one of these as I mounted my display to a panel using the plastic backer that is supplied with the display. When the display card is mounted to a 1/8" panel, access to the micro SD reader is very limited and so I bought 2, one for each of my projects.
While the theory is good... in practice I was not able to reach in to the SD receiver as the display sits high when panel mounted.
I think a good idea given the location of the SD receiver .. but for me... not as effective as the USB input.