But why?

The whole point is that you can access all the "essential" keys with modifiers like Fn.

I find it so natural to Page Up/Dn using Fn+Up/Dn that when I'm on a keyboard with dedicated Page Up/Dn keys it just seems like this bizarre waste of space.

Plus the keyboard is so big I have to keep moving my hands all over the place! A 75% keyboard keeps everything within distance of the home row, as it should be. Faraway keys are just inefficient and not ergonomic.

There's no need for F36 when you can just use Shift+F12 or Ctrl+F12 or Fn+F12 or whatever you want.

Also, a compact keyboard keeps your mouse closer which is good for ergonomics as well.