And USB as a
cheap source of power makes all of those really cool
devices--shavers, foot warmers, fans, etc. possible.
[So] does a bench supply...
Sure, but you usually can't get a bench supply for under the price of a
fast food burger, while you usually can get a USB "charger". I think
it's pretty nifty to be able to get 2.5W and 5W 5V power supplies that
inexpensively. Of course, they're also not of the same quality as a
bench supply. I wouldn't use them for anything that I can't easily repair.