I'll go against the grain: I think it's an interesting idea for someone that's working out. Dehydration is a pretty serious issue, and if you're thirsty you're already dehydrated. I'm an experienced cyclist, I've trained myself to drink about a bottle an hour during hot weather, but I somehow let myself get dehydrated during a long, hot ride last summer, and I felt bad for the next day or two. Dumb mistake. I probably wouldn't buy this bottle, but for someone new to working out it might not be a bad idea.
Now, whether this bottle is a good thing for Nikon to make...