You can smell the elitism dripping in their examples on the site. Private helicoptors, $31 grocery delivery... most people will pay a little extra for convenience, but this is ridiculous.
Magic feels more like Uber to me. You don't use Uber once, then establish personal contact with that one driver, never using Uber again. The value of Uber is that you can get a driver on-demand, at any time, wherever you are; this is not possible if you just have one driver's cell phone number. Similarly, asking Magic to send some flowers to your girlfriend doesn't mean that you'll never have a use for Magic again. It's a middle man that can provide value repeatedly.
Magic's generality is why it might actually stand a chance. For instance, you could probably use it as a makeshift Homejoy, asking for them to find you a cleaner who will come to your place once every two weeks. Once they find you a cleaner, you won't need them for that particular service again, as you'll have personal contact with the cleaner. But because of their generality you'll be able to find many other uses for Magic most likely.
With Homejoy, you could avoid the middle-man and go straight to the person doing the work. Here, you don't meet the person doing the work and the middle-man is where your time is saved.