Just by using your phone, you could purchase almost anything. No need to withdraw on an atm. No more heavy coins on your pocket. Paying bills, and purchasing tickets without standing on a line. Very convenient and less time consuming. I know we're already using credit cards right now, but using a single currency like bitcoin world wide could really help on transaction, having less error than the normal and faster transfer and of course the security. Do you guys think this could happen in the future of bitcoin?
That's awesome world.

But I think using single currency like Bitcoin is not good idea. If you transfer money to the wrong people (bitcoin use address, not the bank ID, it doesn't show the recipient's name), you will not be able to get your money back. Yes, Bitcoin is a modern, fast, convenient currency, but it's not suitable for daily life. If Bitcoin want to be daily currency, it may need to change. The amount of bitcoin is limited, but our need is infinite. I think bitcoin is not a good choice. In cashless world, Bitcoin should be extra selection, i don't hope it will replace cash.
The biggest problem with Bitcoin is that it's too convenient for criminals. I don't think "mankind" like it.