I think RDTAs have a niche in the market. They are kind of wanna be squonkers, never thought of it that way. However, for my vape style, there aren't many squonk devices that will satisfy me. I vape pretty high wattage. Depending on the coil, 80-100w.
The majority of squonkers are single battery mechs. So I'd have to build around .12 ohms, make sure my connections are clean, and carry around probably 3 batteries.
With an RDTA, I can put it on any mod i want and go. Assuming it works lol.
For me to get into squonking, i would need a regulated, 2 battery mod. The only one I can think of is the Lost vape drone and at $200, i'll pass lol.
The Drone has been discontinued. It had problems anyway. For a dual 18650 squonk mod look at the Geekvape Gbox.