That sure is thin. A better comparison is the PPS with the Kahr PM9 to see which one is even thinner.Unfortunately I do not have a PPK, but here is the PPS snuggled next to an H&K P2000SK if that helps you at all putting the width in some sort of perspective.
http://i73.photobucket.com/albums/i229/stoshie/PPSHK.jpg
If you like thin pistols, very likely you will be happy with the PPS, it is thin, and don't think I would even want it any thinner.