It is absolutely true that everything around us can be called a Pyramid or a Ponzi scheme. Pension system, banking system, currency system of Fiat money, credit and Deposit in the Bank. Generally any system where there is money, can be considered scheme fraud. The only question is legitimate is fraud or not.
Many people don't know bitcoin but hear from the media about rising bitcoin prices, then call it fraud or ponzi scheme. How wise before commenting on first know bitcoin from A to Z, its history, how to use it, its advantages and disadvantages, etc., so that it can be concluded that bitcoin is truly a digital currency.