For me, it was a matter of simplicity and aesthetics -- not so much for looks but just the psychology of having less stuff on the bike. But it may also be that among the commuter crowd, there are a lot more "put together" bikes, and a 1x rig simply involves less putting together. For instance when I switched to upright bars on my fun bike, I had the choice of moving two shifters up from the downtubes, or just one. When I got the rear shifter wired up, I really wanted to get on and ride, not spend more time in the garage.

Today both my bikes are 1x3 with old IGH's. So far as gearing is concerned, I find that a 42/19 ratio, using the smaller ring from the old road bike, is "just right" for my commute with moderate but not insane hills. My low gear is close to the typical low gear on a road bike, equivalent to roughly 42/25, so it's not absurd to think about getting up hills with it. On downhills, well, I can live with the indignity of coasting when I run out of cadence.

One thought about gear range: Many of us can probably live with a small fraction of the gears found on a typical modern bike, but the question is which gears. It depends on so many things, such as your terrain, physique, etc., that it makes sense for bike makers to offer a wide range of gears that can accommodate pretty much everybody. But in the commuting situation, where the terrain is the same every day, you can narrow things down.