Sure, but they don't do that with their phones, and like hell I'm carrying this thing around without a case (which is also why they don't bother to make their iPhones so they're easy to use caseless, or make them so the backs are flat without a case—everyone uses a case unless they're trying to signal "I'm rich enough that if I drop this and the screen shatters I'll just shrug and buy another immediately, and if it happens again next week, same story"). That was a problem with my Mini when I first took it out of the box, but it was in a case soon after and that stopped being a problem—and I would buy this as an explanation, if they hadn't kept the original design for the first 3 generations, and if they seemed to care about that for other devices—my 4th gen iPad Pro's like that, too, so it's hard to use in-hand without a case because the bezel's tiny—but of course I'm going to have a case on it, so it hardly matters.
[EDIT] in fact, with a case, this thing's gonna look downright fat. Maybe they just couldn't fit as much battery as they needed for these newer chips & screens, in the old size?
A phone fits easily in the palm of one hand whereas a tablet usually requires a stronger grip since it’s much larger than a phone. Just take a look at their product page and you’ll see a model holding the iPad mini with one hand and their thumb already touches part of the screen. If the bezels were thinner it would cause more erroneous inputs. So why engineer thinner bezels when it’s not practical to have them in such a device.
Yes, but they don't do that on other models of iPad, not just the phone, and again, most people put these things straight in cases, so they've usually (and correctly, despite complaints on Web forums) designed their devices so they won't be too bulky once a case is added, past the early generations when they kinda needed the bezel for space reasons (though, again, even the now-ancient first-gen mini barely had side bezels)