As others have said, it's not to do with whether you can/should use RDAs on an MVP - it's to do with dual coil builds being - debateably, depending on your materials, your coil resistance, and the kind of vape you're hunting - not worth the effort due to the wattage limit. My absolute favorite topper for my MVP 2 is a Kraken with a single microcoil and cotton running at 1 ohm. I can get dual coils to work, but it takes a lot more fiddling to get exactly the same vape experience, so why bother when it will also burn twice the juice to get me there?
That's *my* preference... if I wanted to subohm, I wouldn't have MVPs. And I get plenty of flavor and vapor from a well wrapped single microcoil.
IMO, what makes the difference when it comes to single coil RBAs is air flow control and the size of the chamber. A well-designed chamber (small or domed) and the ability to adjust your air flow can allow for a very nice vape without needing dual coils or sub-ohming.
That's not to say there's anything wrong with either practice (provided one is educated about battery safety etc), but subohming, dual coiling etc are not *requirements* to get a good vape out of an RDA.
(Edited to add): I had a chance to try a buddy's Magma on my MVP 2.0 a little while ago, also running a single microcoil with cotton at about 1.1 ohm, and it was fantastic. A Magma will be my next purchase. Again, that's just my opinion - not a guarantee that what I like will be what you like - but I was quite happy with the experience!