Why do cryptocurrencies have value?

Answer: Scarcity and people believe in them

Scarcity and people believe in them ✓ — Correct! Like traditional money, cryptocurrencies have value because people agree they do and are willing to trade for them. Limited supply (Bitcoin capped at 21 million) creates scarcity. Unlike fiat currency, they're not backed by governments but by cryptographic security, decentralization, and network consensus. Value reflects belief in the system.

Mining costs determine value — Wrong. Mining costs don't determine value—market supply and demand do. If mining becomes expensive but nobody wants the cryptocurrency, it's worthless. Mining costs set a floor (miners won't operate at a loss indefinitely), but actual value reflects what people will pay.

They replace all money soon — Wrong. Whether cryptocurrencies replace traditional money is highly uncertain and debated. Their current value doesn't depend on future adoption—it reflects present scarcity, utility for transactions, speculation, and belief in the technology.