It's an interesting idea. Do Disney hotels have ice machines? I've never looked. Otherwise I think it would be a little annoying. I don't mind filling my camelback up at home, but when camping, it gets kind of difficult because the only place I feel comfortable filling up is a gas station, and even there, you need a thick skin.
In contrast, it's super easy to fill up a water bottle at WDW- quick service will let you and table service will keep bring you ice water when your glass is low.