While they truly are in different leagues, the 10mm is far more versatile. It is suitable for anything from match shooting to personal defense to medium game hunting. With the ability to go from the low end loads that are similar in kinetic energy to a 9x19, all the way to top level loads that nip at the heels of the .41 magnum, and the ability to use bullets from 135 to 220 grains, it is about as flexible as an autolading pistol cartridge can possibly be.
That said, for deep concealment, 10mm pistols just don't get that small. The Kahr PM9/K-T PF9 are much smaller and roughly 1/3 the weight of the only compact 10mm's; the Tanfoglio Witness Compact and the Glock 29.