No we're not!I'll use the XXLs when I travel simply because it's easy to toss a few into a baggie, bring along a couple of eGo batteries and maybe a small bottle of liquid. Much more easy to get through security, easier to pack, no worries of tank leaking due to pressure changes on the flight, etc..
As to the advice and observations in this thread? There's very little that I can add, especially since the information is so very spot-on.
One poster did mention that the tank is just a tank, and with that, I agree. It's just a reservoir for the liquid and saves having to frequently top/fill a carto and automatically keeps its polyfill at a proper level of saturation. I went with a cheap option when I got my first set of tanks, I wanted each of my favorite liquids tanked and went with the pyrex Smok DCTs since they had a low entry cost. Now that I've settled in and decided that carto-tanks are my preferred method? Well, the Smok DCTs are essentially "disposable" since the caps are fixed and the seals/o-rings can't be replaced. When they fail (not a matter of if, I do take care of them, use a carto-insertion tool, but they will fail sooner or later) I will replace them with a higher quality glass tank. But since they will fail at various times, the hit to my budget won't be all at once.
Great topic, great discussion, invaluable information. Especially for those who are lurking (we know that you're out there!)