Bitcoin is not fake, it is true that you can earn money using it. There are many ways to earn bitcoin such as investing, trading, mining, etc. Bitcoin is not a scam, the scam is those people who had a bad intention to bitcoin. Their strategy is present bitcoin to the people and say to them to invest money and sooner or later it will become double. But truth is, after they invest they will cut the communication with the people who invested. That's what you call "scam".