The differences of bitcoin and $ actually is a lot, but some of them are :
1. Bitcoin characteristic is independent directly from any government
2. The transaction of bitcoin is very transparent just like a cash book of a bank that so far just accessed by the accountant of that bank, but bitcoin
with blockchain technology is allowed to be accessed by anybody.....so the transparency is very high.
3. Bitcoin is allowed to be transacted by peer-to-peer, not via a bank which can shorten the procedure and bureaucracy, and of course the cost.