I myself am primarily a weightlifter. I lift a half hour a day, every day. During the summer I do cycling on top of that.
Yes, I found that when I first started taking creatine, it caused me to pee like a race horse. Now, six months later, the problem is entirely gone. As for drawing water into the muscles? That didn't seem to happen with me at all. I didn't experience any immediate weight gain.
It's not something you could just take as needed. It should be used every day, or not at all. Different people are going to have different experiences with it, but I have found that I have much more energy, all the time. Also, being a muscle support agent, it will aid the heart and the lungs, which, of coarse, are powered by muscles.
Maybe some different athletes could flesh out this discussion? Endurance guys?