Why would somebody want to exchange something (dollars) for nothing (bitcoin)?
We are back to the original question.
Long list of potential uses for bitcoin? Name one use of bitcoin except dumping it on the next guy?
Think of bitcoin as a currency and you'll realize how stupid you sound.
You exchange bitcoin for goods and services because you know that people consider it to have value. Just like the dollar, gold or other commodities.
Probably worth doing some more reading