One of the main reasons for the popularity of bitcoin in 2020/21 was the COVID-19 pandemic. The collapse of the global economy as a result of quarantine measures forced the world's leading central banks to take unprecedented measures to save and support the economy by issuing trillions of dollars of unsecured money.
Of course, this is reflected in the US dollar, which is depreciating against the world's leading currencies. Zero interest rates attract people to take out loans more often, making deposits unprofitable, as well as investing in bonds, whose yield is almost zero. The only source of profit was the so-called risky assets: stock markets and cryptocurrencies.
Stock markets, like cryptocurrencies, have provided investors with high returns, but if company shares are used as an investment asset, then bitcoin and other cryptocurrencies are also used as a deflationary asset, which helps to protect capital from depreciation.
In addition, bitcoin and other cryptocurrencies allow for much cheaper, safer and faster cross-border transfers of large amounts of capital. An asset that allows you to transfer value literally from hand to hand on such favorable terms, bypassing the banking system, is in high demand, which will only grow in the future.