Why would I want to use this over figma? The sidepanels and floating toolbar are ripped directly from figma (to the point I would fear a lawsuit). Figma is already a very clean UI, which tries it's best not to shove too many features in your face. Whiteboard, presentations, dev mode are all hidden behind menus. "no plugin support" seems like a very odd thing to flaunt as a feature. Many of the most popular use-cases of figma, such as interactive prototypes, svg creation, html/css exports are all impossible in this tool.
Then, there is the problem of this being maintained by a single person. Components are essential to any serious figma user, good svg and image handling is important (svg is buggy in my testing), selection colors is vital, color palette is important. When can users expect to see these features if the maintainer is busy hunting down bugs?
This is a technically impressive product, but I struggle to see the market plan. I personally hate distractions in software, I go to great lengths to debloat and disable features to make my computer interactions smoother, yet figma is possibly the last program I would want to clean up.