I thought the same at first but some memory ("gaming memory") might have pretty extensive heatsinks that make it wider than just this adapter PCB. So yeah, you don't win much but sometimes a few millimeters make the difference between fitting things in or not.

It gives you a profile that's very slightly thinner at the bottom, but I've never seen a cooler that spills past the CPU where the bottom inch is wider than the second-most-bottom inch.