It'll open the door for more ambitious webgames and web apps that use the GPU.
https://en.wikipedia.org/wiki/Infinity_Blade
Game demo, https://www.youtube.com/watch?v=_w2CXudqc6c
The only thing I like in Web 3D APIs, is that outside middleware engines, they are the only mainstream 3D APIs designed with managed languages in mind, instead of after the fact bindings.
Still waiting for something like RenderDoc on the respective browser developer tools, we never got anything better than SpectorJS.
It isn't even printf debugging, rather pixel colour debugging.
Hence one of the reasons why it never took off as Flash replacement, and indies rather focused on native mobile games.
It is hard to sell an experience, when there is zero control over the hardware acceleration.