Bitcoin's fixed supply of 21 million coins, enforced by its protocol, poses challenges to its suitability as a global currency. While scarcity can drive value, it limits flexibility in responding to economic demands. Global currencies often require adjustable supply to manage inflation, deflation, or economic crises, which Bitcoin's rigid cap cannot accommodate. This could lead to deflationary pressures, discouraging spending and hindering economic growth. Additionally, the fixed supply may exacerbate wealth concentration, as early adopters hold significant portions, potentially undermining equitable distribution. However, proponents argue that this scarcity ensures stability and protects against fiat currency devaluation. Bitcoin's divisibility into satoshis mitigates some concerns, allowing microtransactions. Yet, its volatility and lack of centralized control make it less practical for widespread adoption as a global currency compared to fiat systems with elastic supply mechanisms.