Yes, but when I look at the files I still see flows.json. Would it be safe to delete it because it will never be used as long as projects are enabled?
Well, I was just playing around with it. But I assumed since there is support for multiple users with separate Git settings, this is intended to have multiple users use the editor at the same time or at least one by one. Isn't it? How is it supposed to be used?
depends what you want the answer to your initial question about going back to it you want... If you don't ever want to go back then yes delete. If you want to go back (by disabling projects) then you may want to keep it.
It is meant so the user of Node-RED can develop and switch between multiple projects - eg like you do with other dev tools. It is not multi-user per se... though of course different developers can work on the same project(s) - eg like they do on git today. If you really want multi user in the same platform then you probably need to look at something a bit more sophisticated like Flowforge which adds that and more on top of Node-RED.