One of the largest roadblocks I have in defending bitcoin (and cryptocurrency in general) is when people compare it to a Ponzi scheme.
There is plenty of bitcoin FUD that is easy to defend, but when people pull the Ponzi-card, that is when I begin to get agitated. This is because I don't have a sound argument to combat this claim.
For those who are not readily familiar; A Ponzi scheme is a form of fraud that lures investors and pays profits to earlier investors with funds from more recent investors. The scheme leads victims to believe that profits are coming from legitimate business activity, and they remain unaware that other investors are the source of funds.
People compare bitcoin to a Ponzi scheme because the price increases when more money flows into the underlying asset. If I buy for X and sell for X+100 that 100 profit of mine came from another person who bought into the scheme after me. In the eyes of many, this is dangerously close to how Ponzi schemes generate value.
What is the best argument against the Ponzi scheme narrative?
In what ways are Ponzi schemes different from bitcoin?
How do they generate value differently?
I can see where the comparisons come in but a Ponzi scheme is an intentional scam, which is not a fair representation of Bitcoin which has a very functional usage as a conveniently trade-able currency. You'll find people who use terminology like this struggle to understand the blockchain technology behind it or intentionally mischaracterize it because they themselves do not assign any value to it. However even if you are not a fan of Bitcoin, you should be able to see that it makes transfers of money without centralized third parties possible across borders, which can save all sorts of people from paying unnecessary fees to middlemen and banks. Even if you are talking about selling to a greater fool theory, that can be equally applied to any speculative asset like cars, wines or art.