Nick Diaz wrecked Scott Smith to the body before the finish as well. And Pete Sell dropped Scott Smith with a body shot before running facefirst into Smith's fist.
I see a pattern.
Diaz wrecks pretty much everyone with body shots before he finishes them, Shamrock, Daley, Smith, etc. it's awesome.
Body work is truly amazing because you can do all the roadwork in the world and you STILL won't be getting punched to the solar plexus/belly/upper ribs/heart/etc. as you run. It pays dividends in a way that's really only evident in fights that go past the first round, for the reason that nothing really drains a man's conditioning (and will to fight) like a dozen or so good body shots, whether it be punches or kicks and knees and so forth. I can almost guarantee that any fighter would be noticeably slower after such a round or two, and it would only get worse as time went on and the body shots accumulated.
Fights like Maldonado-Villante really exemplify this-- many criticized Villante for "gassing" half-way through the second round, but in truth, his conditioning had simply been sapped by judicious, consistent body punching by Maldonado, who has terrible defense but will regularly enter behind a jab to land two/three nice body shots, will counter leads with his own body shots, etc.
The problem is that effective body punching requires commitment. So many fighters try to fell their opponents with one blow to the extent that they will land an otherwise worrying body-blow, yet because cannot discern an appreciable effect in the opponent, simply give up on it because they don't realize that every body shot you land is money in the bank, and the interest only adds up. Whenever you see a boxer crumple a guy in pain with a big left hook or right straight to the body, it's typically only after his body has already been worked well over, and his guts are sensitive to the puncher.
I also just realized that you were implying Smith is weak to body shots, which may be true. But, body shots are awesome and will drain almost anyone.