They dont really work do they? How many titles have actually been greenlit through bundles? Lets count.
1. La-Mulana (Already well known thanks to the freeware version)
2. Akanerio: Demon Hunters
3. Uh....

Yeah thats about it. I know some titles which have been in bundles and then have got greenlighted... But they dont really count.

1. Postal 2, Unepic, Waking Mars, Towns, DLC Quest (In bundles before greenlight)

2. Dawn of Fantasy, AirBuccaneers (In bundle after it was Greenlit)

3. Dead Pixels, Postal, The Journey Down and some others (Never went through Greenlight in the first place)

That leaves TONS of games which have featured in bundles for greenlight and have even featured in Greenlight specific bundles (Greenlight Bundles, Build a Greenlight Bundle) so is there any real evidence that this scheme actually works?