If you mean the smaller terrarium foggers I'd say they are more trouble than a larger ultrasonic room humidifier is and are sometimes more expensive for the same basic technology.The small foggers are meant to be placed inside the cage somewhere, but that also puts them right near your cham, free ranging feeders, and a lot of moisture which can shorten its life. A humidifier can be placed outside the cage (you can direct the fog into the cage with pvc or flexible tubing) where it doesn't tend to get damaged by condensation and your cham and insects can't touch the nebulizer disk or fall into the reservoir. Both fogger and humidifier need to be cleaned and sterilized regularly.
They have their uses if your area is dry and daily misting doesn't keep your cage humidity stable enough throughout the day. They are not so much a source of drinking water as a humidity boost when cycled on a timer.