I'm the type of person who thinks that having devices that can be charged by USB is a great thing. I do it with my cell phone as well, as my PSP, but I kind of draw the line at a vibrator. Seriously, who thought this would be a good idea.
Now I'm not an expert of these devices, but I do know one thing, when they're not in use, they're usually hidden. As well, when you need batteries for such devices, grab them out of the remote control. You're not going to care what's on TV, until after your done. These things are suppose to be "discretely hidden", not sitting next to your keyboard on your PC.
Also, house guests are going to see that you're charging your "battery operated buddy", and know what you did the night before. Do you really want everyone to know that you were using power tools to have an orgasm? What if your mother shows up? It's definitely a interesting conversation piece. I've got Tomb Radier, Snake Plissken, and Bob and Doug McKenzie action figures in my living room, and someone else has a vibrator display.
The really bad news is that I might have figured out the thinking behind the USB vibrator. A "user" is on her PC, looking at ....PORN, gets a little excited and her battery operated buddy has finished charing and OFF WE GO!!! I really should think about stuff like this, but I know I'm right. I've recently read that more women than men go online these days. I think this is social network is more popular than porn online these days, but I guess for those certain moments, they have their hardware beside them now and it can be easily recharged after.
I really shouldn't be thinking about stuff like this.
My 2 Bytes.