I can't speak for Provape, so everything that I say here is purely my personal opinion. I've been a fan of the Provari for one and a half years. I have two standard size and one mini.
Why more than one you ask? Well, I purchased two myself and my most recent one was a gift. If you follow the Provari sub-forum you've noticed that a great many owners own more than one. Even though the Provari has a great track record of being a very dependable and durable mod, I don't think any of us could stand to be without our Provari in the rare event that it should require to be sent back to the Maker for repair. Therefore, a backup Provari for the primary one is nearly a must have. We all have other mods as backups, but if they aren't a Provari, its just not the same.
Only one of my mods has VW, and I never use that function on it. All of my juice attachments are purchased in a standard/high resistance, so even when I change tanks I don't have to worry about changing the voltage because of a difference in ohm ratings. I change flavors frequently throughout the day, and I adjust the voltage accordingly for each flavor's sweet spot. VW would not help me with this, in fact it would be a hinderence as I would still be making an adjustment in VW mode. Not everyone wants or needs VW.
Provape has been selling Provari's as fast as they can produce them for almost 3 years now. They make a very simple and basic VV mod which does what it does extremely well. It is built with attention to detail. It is known to be one of the most accurate and precise mods in delivering power to the atomizer using variable voltage; an industry leader and gold standard example.
If you follow PBusardo's in-depth video reviews, he does extremely detailed tests and graphs of all the mods he reviews. I've noticed that many of the mods are pretty accurate in VV mode, but the ones which have VW ability often fall in accuracy when in that mode. Just my opinion, but perhaps the design team at Provape do not believe VW is an accurate method of delivering electrical output.
Regardless, I am of the group of people who believe VW is only another way to get to the same place. I've read of people who have purchased a VW mod specifically for that function, and who then learned it wasn't so "set it and forget it" as advertized. Many of these people went back to using the VV function.