I have full sets in all three sizes (1/4" ,3/8", & 1/2") with locking flex ratchet handles, and I would hate to wrench without them. If forced to choose, I would take these over standard square drive sockets, without hesitation.
I don't see the gimmick in them. You guys do realize you can use these even when the pass through feature is not needed, right? If that is all you see when you look at them, you're not taking a very broad view.
They're stronger than square drive sockets. I have broken (only) a few sockets, and I've twisted a square drive lug or two off a ratchet, or extension in my time, but I have not yet broken one of these.
They're also have a lower profile than even a low profile socket on a low profile ratchet. Almost a full inch. That's the difference between fits and doesn't fit, fairly often.
I have found only two drawbacks to them. There is no swivel extension for them, and you can't use them on power tools (impact/air ratchet, etc). The impact thing is no big deal (not supposed to do that anyway), and as for the lack of a swivel, well the one or two times a year I need a swivel to reach something I dig the standard sockets out of the back of the toolbox.