[angersock]

I've got some decent experience with both OpenGL and WebGL. It's simply not worth the effort to learn for 95% of whatever you'll be doing--you end up reinventing a broken subset of what's already there.

Three.js is taking care of a lot for you, and it's not a bad thing. It's doing scene graphs, matrix math, GL setup and teardown code, shader setup and teardown, buffer setup and teardown, camera math, and much more.

Use a bloody engine unless your explicit goal is learning something arcane.

[nawitus]

If you want to learn WebGL then you need to use WebGL. Using an engine can be a good decision for a project, but not a good way to learn WebGL.

[angersock]

Quite right--but the utility of actually learning WebGL is questionable.