It definitely isn't magic and in my opinion if someone claims that it is then they are probably trying to sell something. I don't think the OP was trying to claim it's magic.
I only have a basic understanding of aimpoint but I have spent time with Mark. I don't see how anyone could possible calculate the slope by using their feet like someone here has claimed and that's not how it was explained to me by Mark. If they could then why does everyone using aimpoint carry around a digital level. Maybe you can get close but so say this putt in on a 2% slope instead of 3% or 1% because they felt it in their feet is kind of ridiculous. The feet help you find the zero line, fall line, uphill direction, or whatever else you call it...atleast that how it taught to me.
In my opinion, the real advantage of Aimpoint comes if you play the same courses a lot and have time to map out the greens prior to playing. You can map out the slope percentages in different sections of the green, the zero line angles, and you would need to figure out the speed of the greens. It is a lot of work to do it correctly but if you have all that then you can calculate the break within seconds of looking at your chart. If I played the same courses or was a member at a club then there is no doubt I would have every green mapped out and use aimpoint on every putt. You would be crazy not too...it's almost like cheating. If you don't have it mapped out prior to playing its pretty difficult and slows everything down on anything other than a planar (flat but tilted)putt.