Scarcity is a strategy for most of the blockchain cryptocurrencies to make themselves more valuable.
Yet, scarcity is not a true value.
The true value originates from being backed by an asset.
“Bitcoin's fixed-supply scarcity is most highly valued because it is coupled with accelerating demand, proven use cases and recognized desirability,” Bitcoin's supply is capped at 21 million coins. (There are currently between 18 and 19 million bitcoin in circulation.)