Bitcoin is like cash - you don't need to go through a bank or credit card network in order to transfer it to another person.
It's better than cash because you can do this over the internet.
It's way better than all other monetary instruments because it is programmable money: you can basically treat bitcoins as symbols to represent anything (like titles to property, for example), and have the distributed peer-to-peer blockchain mechanism enforce title transfers in a provable, reliable way without any notaries.
Some people are working on setting up fully autonomous corporations using Bitcoin infrastructure. These will be essentially computer programs that own and spend bitcoins, and sign and enforce contracts, without any human employees.
Because its cashless payment and that is one of the advantage of bitcoin. But i think its better if we also have cash because is very convenient to buy in some store when we have some cash.