As you can see above, Some contacts seem to be longer than the rest. Also, on the SD card (2nd from top) the last one seems to be thinner and also closer to the seventh pin.
Why not just uniformly place all contacts of same sizes at uniform distances??
The power and ground pins stick out further, so that power is applied/removed before/after the data pins are connected/disconnected.
Pins 8 & 9 were added to the MMC format in making the full-size SD format. So there was not room for a full-sized 8 (maintaing backward compatibility), and perhaps they learned a thing or two about applying/removing power first between MMC and SD (or about making it cheaper without an extra switch if they extended the pins).
