Really ? To me they're the greatest invention since sliced bread :-)
Seriously it's a great way to travel light and compact. These things are cheap, extremely compact and light (more so than even the Nokia travel chargers for my phone and 770), and have NO wires -- just a plug.
I hardly ever carry a laptop, but do tend to have several mobile devices with me -- the phone, the 770, the mp3 jukebox... with that tiny plug and a couple of appropriate USB cables I can keep them all juiced up. That's three adapters you don't have to remember packing, carry around, and try not to lose en route...

As I had to buy a CA-44 adapter because of Nokia's different adapter plugs, I could even get the cable with the large one and use it to charge both the phone and the 770 with the adapter.

Of course that will depend how terrorist a price Nokia will fix for such a simple item :-)