Why does RGB use 6 hex digits?

Question

I understand that RGB encodes a color with two hex digits corresponding to the Red, Green, and Blue components. For instance, #ff0000 is pure red. And I understand that each hex digit represents a number from 0-15, or 4-bits of information. But how is it possible to represent every color with 32-bits? Why use two digits for Red and Green and Blue? Why aren't there, for instance, three digits per color?

Answer 1

I dont really know if any of this is related to hardware and whether we can even make colors to such detail but a third hex digit for colors means we will have colors with 4096 times more detail, (meaning if we have X color combinations currently, then we will have 4096 * X colors) which we simply dont need, since human eye wont be able to notice the difference, even in our current color system, let alone one much bigger.

So you'd be sacrificing efficiency for nothing in that case, like watching a movie on 600 frames per second while your eye can only process 60.