The founder recently went on invest like the best and explained it top to bottom, they started as a broke agency and grew from there quite fast. I forget the details but I would imagine they are financed quite heavily by LP's
Yeah, I think exporting a scene from blender as glft/glb, and then using these tools to bring your exported 3D file to the web, is one of the more approachable abstractions.
The reason you'd use gltfjsx (which that example doesn't) is to have fine grained controls for every node in the scene graph. In the case of the watch, this would map to having a component for each mesh or gear, which can be controlled with mechanics/physics.
Depending on one's skillset, you could use a dcc tool like Blender + three.js to make creation of these visuals and interactions much simpler. Have a look at gltfjsx + react-three-fiber [1] combination, which themselves are abstractions over vanilla three.js.
With that said, the raw webGL approach here is arguably more educational, so goal achieved I think!
Understand the spirit of this, but probably not true. I don't think Xiaomi, or any big tech company, needs to break even on their new model releases.