I feel a lot more comfortable going over curb cuts on a bigger tire. This makes it worthwhile for me. Unfortunately, I bought some cheap tires for my mtb commuter, and now I wish I hadn't. They are heavy and really feel sluggish. It is nice to be able to ride them wherever I want without issue though.

I'm pretty sure that the trend with the tubular tires that racers use is towards bigger cross sections. They have the additional advantage that it's fairly difficult (often said to be impossible) to get a pinch flat with a tubular.

rims have a width rating. I can't stand the look of really narrow tires on a 26" rim, so I went with a 2" tire. Probably one reason I don't like them