Auto-snap, and most importantly inability to rotate, allowed my 1.5yo kid to solve puzzles when he wasn't yet able to solve wooden puzzles well.
After an intense period of solving those non-stop (I believe it's first time he strongly experienced the positive reinforcement of winning a game), he also easily does the wooden puzzles.
I don't have any data on whether that's indeed a win developement-wise, but I'm excited that easy software tweaks (which would be impractical in physical product — how do you stop one from rotating pieces?) can dramatically affect kid's ability to engage them.
My daughter fell in love with a similar non-rotating tangram game at that age, and that's why it came to mind... tangrams are something that tablets do really well.
That said, I do see what they mean about rotation. My son took some time to learn to play Amazing Alex (Rovio's Incredible Machine remake) because of the clumsy rotation UI in that one.