Well, given that Squarespace/Wix/Weebly etc. are selling Dreamweaver-as-a-service (plus hosting), I would say there's a lot of demand still. Pinegrow seems like it would cater to someone slightly more technical (since you need to figure deploying/hosting), but not willing to entirely learn the frontend stuff just to make a simple site. I have plenty of sympathy with that, it's better than going with WordPress for a four-page brochure site, at least.
It's definitely a useful tool for more technical oriented people too. Someone would definitely need to have his/her front-end chops in place to work with Pinegrow without frameworks.
Is that such a bad thing, in an absolute sense? Sure it made a mess of code (well, early versions, at least) but it enabled people who don't/can't/won't code to put content on the web fairly easily. I know I used it as a tool in the early DIV/CSS days to shunt stuff around quickly, before diving in to clean up the code afterwards.
Sure, but I'd then suggest it almost makes things easier - today's internet consumers are generally expectant of a certain range of formats, rather than the early CSS Days' DIV Free For All. A neat contemporary version of Dreamweaver, with a focus on CSS/Grid, Responsive layouts, etc, could be great!
This is different from Dreamweaver in a lot of ways. It's not like Webflow either, which writes code for you, quite in a verbose way and without real support for lots of niceties, like CSS Variables.
Pinegrow lets you choose a framework or allow you to write code yourself, as you wish. If you choose the latter, it just gives you visual tools to create code that follows the standards.