Some good reasons why you use bitcoin.
1. It is fast. Transactions are instantaneous and confirmation times are usually done withing 10 minutes.
2. It is cheap to transfer any amount of money anywhere. Fees are insignificant at this point.
3. Your bitcoin are your alone, they can't be blocked by bank, IRS or any institutions.
4. There are no charge backs.
Great points. I would like to add that it is convenient. You can transact anywhere anytime without the need to actually exchanging cash on the country where you want to use it.