I use them wet and unwet (like that? "Unwet"), can't see much difference.
The only reason I can see for wetting chips is to retard their time till they can commence smoking. Its my understanding that the sweet spot for smoke absorption is 100 to 140 IT (internal temperature), by wetting the chips its allowing the meat a chance to start warming before the smoke hits it. Thereby giving the meat to get closer to that sweet spot range before smoking.
Also it may also add a chance for the smoker to come up to the initial set temperature. That allows it a chance to to change from continious high heat (constant temperature to the chips) to a shorter up and down heater or modulating of the hearter to possibly allow for a longer attempt to start the chips again to smoldering.
Both are just my own ideas, but I am pretty sure that the water in the chips towards humidity can add nothing to help.
Also remember that dry chips in a tray over high continious heat, with heavy air flow can not only combust but explode (I swear!). Its pretty cool to see that reloader shoot out the side! Make sure you don't leave it in an unsecured position when only using dry chips.
Pretty basically what Mule said above in one sentence......<chuckles>
EDITT
BTW I see you are new, when you get a chance, drop by the "Roll Call" forum and sign in so you can get a full howdee from folks. Also when ya can, click on the profile icon on the above task bar and let us know something about you. If nothing else your location. It can help with questions sometimes as thing may be different in MAine from Hawaii. Look forward to meeting you.