3D graphics and AI are two completely different things.
If you do a good job at learning just one of them, whichever it is, but learn it so you master it (which won't be easy), you won't be disappointed with the income at the end (even 10 years from now).
But nobody can tell you which way to go...
It really depends on what your goal is.
True, usually the auxiliary stuff is rendered, but not necessarily.
The site could or could not give a damn about those useless request. In most cases, they don't give a damn, but I could build you a prototype website that cares about those,
and if not...