On multiple occasions here in Idaho, savvy coaches have used it when they've either had a talent deficit, have been trying to resurrect a previously unsuccessful program, etc.
I can think of at least three different times where Idaho coaches implemented a wing T or double wing and won state titles in the second highest or highest division.
The problem I've seen it run into is that other teams start copycatting, then opposing teams get wise to the scheme. Some programs stick with it and maybe eek out a win or two they wouldn't otherwise get, but it ultimately seems to boil down to talent level after a while--like any other scheme. At least once they reach the playoffs.
But yeah, if you have a good personnel group and are the only ones running this, it is an utter pain to defend. Very hard to keep a team from grinding it out 10 yards when they use all 4 downs and rarely run the risk of negative yardage plays.