GL4 tesselation feature

I see this has been added to OpenGL and I wonder why. I suppose the major reason is games using curved surfaces internally and then tesselating them for render? If so, what kinds of curved surfaces are being used these days? I used to hear about curved triangles, back in the day, but know nothing about current developments. What is being used these days?

What’s use is displacement mapping !

The rest of the curve things remain the same.

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