to me, it's convenience. I use cartomizers that have 3.2 ohms of resistance. They SUCK when using a 3.7 volt device, but at 5.5 volts they are awesome. I make DIY juice, and it's tough to justify using a new cartomizer for each new flavor I make, so I test them with atomizers. If I were to purchase standard atomizers, I would have to lower my supply voltage to get the same power as I do using a cartomizer, because standard atomizers have less resistance. Instead, I use high voltage atomizers, so I don't have to do as much voltage adjusting.