Not convinced that "Tanks" are needed because of the device, no matter which device. That being said, I use nothing but VISION Tanks of one form or another. My reason, I vape continuously. . .several tanks a day. Even with an 4.5mL tank I'm refilling it at least 3 times a day. Some may wonder why I don't go with a box mod and a 15ml juice supply, or some other really large quantity PV system. I'm partial to "tube" mods, and refilling a screw top tank just isn't that inconvenient for me. There's plenty of reasons to use a tank, but being VV isn't one of them for me. JMHO
Cheers,
otrpu