|Upcoming Samsung Galaxy S8 Concept|
I guess maybe it "looks cool" to some degree (though I'm not sold on it), but good design isn't really about looking cool or trendy. Trendy designs tend to end up looking dated very quickly. Say what you will about Apple, but their iPhones all hold up fairly well, in terms of appearance.
Good design is also about having a functional device. Given that most of these will end up in cases (since those that don't end up in cases, end up needing repairs, almost inevitably), the phone design should accommodate that, and I've yet to see a "bezel-less" phone which does.
Beyond that, the bezel provides a boundary between the contents of the screen and the surrounding world. For me, that's a good thing, providing a sort of visual breathing room and making the contents of the screen easier to distinguish from the surroundings.
Earlier this year Xiaomi has launched the Mi Mix a 6.4-inch bezel less phone, the problem is that we saw an all screen design on the new xiaomi mix, and the drop tests basically showed that the slightest impact will destroy the corners of the screen. you need some bezel to act as a buffer.
Bezels also give you a non screen place to grip the front of the phone, and they help keep parts of your hands and fingers from touching the edge of the display accidentally without necessitating additional software to handle "edge detection" and disregard spurious touches.
Honestly, all of these S8/iPhone 10th Anniversary rumors just make me really excited for the Pixel 2. The Pixel is already an utterly incredible phone; if Google actually feels the need to be competitive on all of these new hardware fronts (and that is a big "if"), then we'll be in for a real treat.