The only thing you can be certain of is that nothing is certain. Bitcoin is not a scam and people have made money with it, but it also has a variety of flaws that prevent it from achieving universal acceptance atm, the most apparent being lack of practicality (few businesses accept it), and insecurity (exchanges can be hacked and keys can be lost- no one guarantees your money). Once these two problems are figured out the new world cryptocurrency will have been established.