If I want to buy stocks or invest money I can easily invest with real $. Why would I convert my $ to bitcoins?
If I want to gamble , I can simply gamble on websites that require $ as currency, why would I convert it to bitcoins?
What's the difference between Bitcoins and dolars? What does bitcoin bring to the table that real $ don't, less taxes, more income?
Digital currencies like bitcoin and other alt coins has advantage and this advantages compare to flats or cash. One of the advantage of it is just what you have said fast transaction and I'm adding anonymity, secure and you can transact in any part of the world as long as there is an internet connection.
Some of its disadvantages are, You cannot use it without internet connection, You cannot use it without electricity, Its price is unpredictable it can easily rise and it can easily go down. If you lose/broke(can't repaired) the devices where you saved your PK's and recovery stuffs you're doomed.