Actually, there are a lot of reasons to kiss, but knowing that lips are one of the most sensitive parts of the body (100 times more sensitive than fingertips) is a good reason, for sure! Of course, how YOU experience that sensitivity may be different from how someone else does, because how we feel things is subjective, and human bodies vary quite a lot.
Lips and fingertips have the most touch receptors (more than in the genitals, even) with far more in the lips.
However, because our fingers and lips are exposed to the air and used every day, we learn to filter out sensation, so we can get through life without being constantly overwhelmed by input from our surroundings.
That said, when you focus in on your lips, they can pick up far more sensation than any other part of your body, and can be a source of pleasure, even orgasm.
Which might explain why some people love giving oral as much or more than receiving. Not only do they get the pleasure of GIVING pleasure, but they also receive delicious sensation directly through their lips.
And, of course, there’s kissing.
A more delightful pastime I can hardly imagine.
So, if you’ve not really focused on the pleasure your lips can provide, perhaps it’s worth some experimentation, alone or with a partner.
Perhaps add lip stimulation through touching, kissing, or oral to your next sexual experience, and heighten your orgasmic experience.