This Bitcoin allows you to send or receive money only via the internet. In addition, Bitcoin can also be cashed into rupiah. Bitcoin to rupiah exchange can be done through the exchanger site or by coming directly to a Bitcoin ATM.
The difference between Bitcoin and a national currency is that they are in limited supply, unlike the national currencies that the country's central bank can continue to issue. Bitcoin only has a total supply of 21 million which is controlled by the underlying algorithm. Besides, Bitcoin does not have a single institution controlling its network.
Transactions for Bitcoin and other crypto assets are also irreversible, which is different from other national currencies. The Bitcoin system also doesn't have a central validator which makes you a semi-anonymous user. When sending or transferring, the system only checks if you have Bitcoin to send and does not check identity.