Almost everyone that I know that buys one spends very little time thinking about what they stuff might actually "do" and instead want an iPad because that's the new cool gadget.
Yes, some significant percentage of early fit this category, its a classic early adopter profile. Some others likely have a very specific task in mind, from "watching videos in [Airplanes|Ranger Stations|etc] to [Important business function that would justify spending 10x more than it costs]. Don't make the mistake of assuming "People you know" = "World of all iPad consumers"
Which any decent tablet will do, but the others all seem like iPad ripoffs (as I guess they are), so people aren't interested in them.
Or perhaps they already have an iPod/iTunes library and see value in not switching. Or they looked at the application environments and chose Apple's locked down model of reliability of Andriods model of openness at the cost of instability/risk.
I just think people are first interested in the product, THEN its usefulness
That will get you through the early adopter phase, but without some sort of "Killer App" that the tablet does better, it will be a niche product that dies out (again). The vast majority of folks don't have money to bun experimenting with toys, if they don't have a VERY compelling reason to chose tablets over competitors (iPod's, Kindle, Netbooks, desktops, etc). Keep in mind the 5% rule too, if it works for 95% of what you want better but can't do the last 5%, it may get tossed aside as unworkable. This is why so many rural residents drive trucks, a car would be better 95% of the time, but they can only afford 1 vehicle and need the truck that 5% of the time, so they buy a truck.