It's wonderful to see someone dive into this as deep. A simpler way to understand the complexity might be to try designing your own font.

Pick up a book on type and start up Fontforge, and off you go.

Be careful though, make an early choice if you are going with 3rd order curves or 2nd order (Bezier) curves.

Going through TeXbook and MetaFont books by DEK is also a brilliant way to learn about all this, with note that they do have an explicit bitmap step in.

One correction though:

  Without it, you wouldn't be reading this right now.

Computers started with bitmap fonts of different pixel sizes. Your console terminal in Linux is still using that, and nothing stops you from using them ("Fixed" has large Unicode coverage and is usually preinstalled) elsewhere too.

So no, none of this tech is necessary for us to read text on computer screens.