Why SHOULDN'T someone buy a Provari?
1 - Current finances don't allow it. The price to get in the door, while not the most expensive, is definitely up there. Cheaper units can keep you from smoking (that's the idea here, right?) just as well as a Provari will. If you don't have $200+ now to spend on a PV, you should not buy a Provari.
2 - Future finances won't allow it. Will you be satisfied putting cheap clearos on your new Provari? Maybe, but there's a strong possibility that buying a Provari will lead you to a new buying spree for better toppers, stainless/glass RBA's, and even top-shelf liquids. If you're not prepared to spend more, especially as new toppers are introduced, you shouldn't buy a Provari.
3 - You don't feel "the pull". This is difficult to put into words, but you'll know if you feel "the pull" or not. Some people get a nagging feeling when they learn of the Provari: "What am I missing in my vape experience?" Beyond the vapor, if the feel of a quality, rugged device in your hand isn't important to you, then you should not buy a Provari.
4 - You've already moved beyond it. You're into mech mods, and/or already own a higher-powered regulated mod. If the feature set on the Provari would be a step backwards, you should not buy a Provari.
I think if you check off one or more of the above, you should definitely not buy a Provari.
Full disclosure: I have a Provari.