How does the use of any language make us better, nobler, or smarter? Language only conveys ideas, and "foul" language, like any other, conveys an idea. Like it or not, the phrase "gosh dang" conveys a much different idea than its foul-mouthed counterpart.
Do people swear a lot? Yeah. Is it a big deal? Not really.
Yes, language conveys ideas, and values. The words you use tell others who and what you are, what you believe in, and what you value. You're always broadcasting messages about yourself with what you say, along with your appearance and actions. Don't be surprised or cry foul if others view you negatively for your choice of expression.
If you don't agree, that's fine. But just spend 30 miniutes browsing threads at DU and you'll probably see what I mean.
"The foolish and wicked practice of profane cursing and swearing is a vice so mean and low that every person of sense and character detests and despises it." -- George Washington
"Profanity is the common crutch of the conversational cripple." -- David Keuck