Also I suggest to not only market to Software engineers but people who work with data like drop-shippers, digital marketing agency, etc.
I actually started this marketing it as "diagramming tool for systems". Talk about trying to be as generic as possible. I want to focus on one segment first, but totally, a side effect is that flowcharts enriched with data acting as a dashboard would be really beneficial to non-technical people to understand e.g. analytics funnel.
Thanks for the suggestion!
Interactive flow charts should be the main selling point, as for usage, it is up to the user.
Also the pricing model, restriction on frames and layers would chase free individual away but they are those who plays a main roles in making something mainstream. I would recommend removing the usage restriction but adding collaborative restriction. A good example for this is how Google Sheet works.
Good luck, hoping to see it being used everywhere someday.