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.
Using bitcoin to transact is much more convenient.
But here's my comment to your post. Fast? Not really. 10 mins confirmation in payment is not that quick. And worse, there are times it goes up to hours. Cheap? Right now transaction fees are simply irrational. They are too significant to just be paid for transaction fees.
The rest I agree. Bitcoin is great but needs development just the same.