Misses the point, though: going from "lockpicking n00b" to "master safecracker" has never taken more than half an hour or so, and in order for these services to be effective you need access to someone's keys. So basically - you're in trouble now if you have friends who are creepers who you have somehow given your keys to but you only want them to have temporary access to your keys, not permanent access. As far as the car - whatevs. I've got a '95 Dodge Stealth and it has a valet key. Won't open the doors, won't open the glove box, will start the car. Give the valet that and he never even sees the rest of my keys, and the key he's got won't open the car door. And as far as the house: Any lock on this page will allow you to set a 1-time passcode that will permit your "friend" to get into the house exactly once. Can't remember who said it - "locks exist to keep out the polite." Still true, even in the age of 3D printing.
There is a difference though between this lockpicking style and the one you describe. Instead of having to seek out lockpicking books and/or tutorials (actively pursuing something malignant), people who find out about the nefarious use of KeyMe probably already use it for their own keys, too. I might be able to find out how to surpass most routers by Googling half an hour - that doesn't mean that I will do so. But if I figure out how to surpass my own router, I might be inclined to use this trick simply because I've done it before. That, and it's a reminder of how perceived safety can be misleading.
We're still talking about turning "random creeper you'd give your keys to but not for long enough to dupe" into "random creeper who has your keys." Intentionally duplicating someone's keys against their will is still malignant, whether they do it with an iPhone or an Altoids tin full of playdoh and a couple tubes of JB Weld (works and well). It's the "lead me not into temptation" argument: that somehow, if it's that much easier to do something you'll do it and that the barrier to entry is the difficulty of the task. If that's the case (and I don't think it is), then the only real change this makes is it empowers the crime-ignorant but phone-savvy creepers.