I disagree. Starting diameter is only slightly smaller than 9mm and it's possible to get .50 cal expansion or larger. What you say would be true if you're limited to FMJ ammo, in which case, it'd be inefficient as a man stopper. (probably comparable 7.92x33Kurtz, 7.62x25 tokarev and .30 carbine with ball ammo) But in a case where you'd need penetration, it'd have plenty of it.
With expanding ammo, wounding should be significant. If you don't think a .308 cal bullet at ~1800FPS can't do significant damage, talk to the hunters using .30-30 at 100-200 yards. While .30-30 bullets do tend to be heavier, impact velocities at common hunting ranges will be comparable to impact velocities and energy levels at SD distances with the .308-10mm
With lighter bullets intended for 7.62x25 tokarev, as Ballardw suggested before, rifle like velocities could be attained, likely at the cost of soft tissue penetration, with an expanding bullet. Which could be desirable, if you're intending to create maximize temporary cavity size.