Three inches, but not a three-inch drop
The number that puts people off this one is the wrong number to look at. Three inches is how high the heel sits off the ground. What your foot feels is the difference between the heel and the forefoot, and on a wedge the forefoot is lifted too.
Look at it side on and you can see it: the platform runs the length of the sole. So the drop through your foot is less than three inches, and your toes aren't being driven down into the front of the shoe the way a three-inch stiletto does it.
Aetrex doesn't publish how thick that platform is, so we won't put a number on the difference. But it's the reason we're willing to stock a three-inch anything in a store full of comfort shoes.