If the dollar begins to collapse, cryptocurrencies could play an important role in the global financial system, but their fate will depend on many factors:

1. Growing Interest in Cryptocurrencies: With the collapse of traditional fiat currencies, cryptocurrencies can become an alternative for savings and payments. People and companies who have lost confidence in fiat currencies can switch to cryptocurrencies such as Bitcoin, Ethereum, and others, which are decentralized and independent of governments.

2. Volatility: Cryptocurrencies are known for their high volatility. In the context of the global financial crisis, their price can either rise sharply due to capital inflows or fall if investors prefer more stable assets such as gold. Panic in the markets can increase the fluctuations of cryptocurrencies.

3. Strengthening Decentralized Finance (DeFi): The decline in trust in traditional banks and financial institutions could lead to the rise of decentralized financial platforms that run on blockchain. DeFi could become an important alternative to traditional banking and lending.

4. Government Measures and Regulation: Countries affected by the dollar collapse may tighten regulations on cryptocurrencies in an attempt to protect their economies. Some governments may ban or restrict the use of cryptocurrencies to prevent capital flight from fiat currencies.

5. Centralized Cryptocurrencies (CBDC): In response to the collapse of the dollar and the growing interest in cryptocurrencies, governments may accelerate the development and implementation of central bank digital currencies (CBDC). These currencies can be used as an alternative way to control the money supply and stabilize the economy.

6. Technological Adaptation: With the rapid increase in cryptocurrency usage, blockchain scalability issues may arise. Networks like Ethereum may become overloaded, requiring infrastructure upgrades and migration to more efficient protocols.

7. Bitcoin's continued status as "digital gold": As the largest and most well-known asset in the cryptocurrency ecosystem, Bitcoin can be considered a safe haven on par with gold. Its decentralized nature and limited supply could help it grow in times of global instability.

So, if the dollar collapses, cryptocurrencies could either benefit by becoming the new financial reality or face serious challenges due to volatility and regulatory pressure.