Lips are ten times more expressive an organ than eyes. They pout, frown, pucker, stretch wide to laugh, smile or take in a huge bite of cake. They smash into straight lines of disapproval. They tremble.
They touch things in a multitude of ways, i.e., a light brush of the lips, a peck, a flurry of kisses. Try touching eyeballs to anything and pain ensues.
Lips are used to spit, sneer, curl, and they can be plump, narrow, full, lavished with lipstick, or chapped and bleeding. Sure sure, eyes can ooze, be puffy, and bruised, but anywhere on the body can be used to demonstrate that sort of imagery.
Lips are so much more. Everyone knows when an athlete, or anyone else for that matter, says the internationally known “F” word with the volume turned low.
They eyes would need help from the surrounding muscles, and eyebrows to get that attitude across.