The purpose of full-length guide rods is to sell full-length guide rods.
Tom hit it on the head. I can see absolutely no advantage.
I'm not sure that's true. I have a pistol built by one of the best 1911 pistol smiths in the business and he uses full length guide rods. I don't think he'd use them unless he found an advantage - at least for his style of building a pistol. That pistol is the most accurate 1911 that I own.
On the flip side - the second most accurate pistol I own does not have a full length guide rod. However, when compared in a Ransom Rest, the FLGR pistol beats the other pistol by about 0.1-inch in accuracy at 50 yards. Either gun being way more accurate than I can shoot.
Without looking at the Wilson website to confirm this - I think Wilson uses FLGR in their Commander size pistols as their experience has shown increased reliability in shorter pistols.