yes, that is a usb port. I'm not absolutely certain; but I believe it is an alternative interface. Plug it into your laptop and it shows up as a virtual serial port. For machines with no bluetooth.

The box is hard plastic, and mine is glued together really well. I tried to pry it apart to examine the components; but I was unable to do so (I didn't want to break it.) The only thing I would worry about is that the BT/Serial module would come unseated. But I think they wedged it in there really well. And if it did, it'd be fairly easy to fix.

So, as long as you don't put the toolbox in a dryer or paint mixer, I think it would survive fine.