The proof-of-work (PoW) consensus model is the mechanism that kicked off the revolution that launched Bitcoin (BTC) in 2009 and it was the model of choice behind many of the popular projects in the early fledgling years of the crypto ecosystem.
As time progressed, other consensus models like proof-of-stake (PoS) rose in popularity, especially as the cost of running mining rigs, the constant need to update equipment and environmental concerns led to the PoW model falling out of favor with many.