disagree and agree with your post
"hot" has become an adjective used to solely describe the physical appearance of a person- you rarely hear someone say "that guy is so hot because he is smart"
i say it all the time, so I disagree with your theory about it being used on anyone
however, i agree because I am one of the few people who use "hot" for something that, as you say, takes time
"beautiful" doesnt necessarily take time- I have met many beautiful people who I never got a chance to know
however, a beautiful person takes time to get to know
and its worth it