Please consider these two sentences (彼女 is a woman):
My sense is that #1 and #2 have the same meaning. Pronouncing きれい is easier, so I have just always said #1. And, I don't think that I've heard "美しい" spoken much, if ever.
What is the difference between #1 and #2?
Regardless of the difference, native speakers still don't say 美しい very much? きれい is what "sounds natural"?