I used to have a little water pot, and I'd use a washcloth to "wick up" the water when I needed more humidity. Just a water dish won't do it, as it will just sit there if there isn't a fan or someway to wick up water.
I'm sure it will. The one I linked to, and similar types, are not designed for continous. They would also contribute with a considerable amount of heat.
But it might work on a timer, 5min every half hour or something ? Or even better controlled with a sensor.