A stablecoin is a crypto asset whose value is tied to assets we care about much more, such as the US dollar, euro, pound sterling, etc.
Stablecoins were created to minimize the volatility inherent in other cryptocurrencies. It is the building block for everything that will be made in cryptocurrency. It is the bridge between the new world of cryptocurrencies with all its benefits (instant exchange, fast transactions, programmability, etc.) and the slower fiat banking tracks that are used every day for everything that happens in our lives.
It's an important hub for consumers and the businesses that use it, so they are subject to intense regulatory scrutiny. Stability is very important in society. People need stable assets when they transact with each other.
If you want to invest in cryptocurrencies and avoid big price fluctuations, stablecoins are a good option. The only thing is that to get returns, you need to use stablecoins in strategies.