Beautiful is all about looks, sexy is all about attitude. A girl can be beautiful and not sexy, or sexy and not beautiful. The best combination, of course, is both. My wife is beautiful and extremely sexy. A past girlfriend was by no means beautiful, but also extremely sexy. Anne Hathaway (for example), is quite beautiful, but not at all sexy.
For me beautifull means beautify of thoughts,beauty of words, beauty of expression,beauty of love,beauty of humanity and that's makes a females gorgeous.Sex is all about attitude.Beauty rule this world and sex follow it .
being beautiful means you don't need to dress in clothes that fit you tightly or make you hav more sex appeal, being beautiful means your naturally gorgeous and anyone can see it by looking at you, so yes beautiful to sexy is a step down