I think they're a lifesaver although we should be careful of what we invest in. Not everything that comes out as a stable coin should actually be considered as one. We have seem them collapse in the past and more will collapse when they can't handle the sell pressure of their investors when things become bad. When it comes to stablecoin, I consider USDT and BUSD as the best options because of the liquidity they have.
This two stable coins has lots of market cap that they can handle buy or sell pressure whenever the market has to give. USDT has had some scandal but none has been able to crumble the market value as it did to Luna UST.