Mind you that hodling stable coins is not investing, your money doesn't accrue any return. The issuing corporation just pegs your money to a fiat currency or to another cryptocurrency, and it can be depegged at anytime or the issuing corporation can become insolvent and thus your stable coin becomes useless.
Well, it's kind of investing because it has the bad side of investing, that you can lose what you invest, but it doesn't have the good side, that you can make money. Let's look at cases like TerraUSD (UST) as examples of this.
I'd definitely save my money in the bank than in a stable coin, a bank has more security and insurance of funds, meaning that if the bank collapses, you will get at least a certain amount of your money back; all of these doesn't exist in stable coins and it is even easier for a stable coin to fail than for a bank.
I prefer the bank and a little cash on hand at home, but as has been said, the answer depends very much on your personal situation. If you live in a place where you don't trust banks very much, or if you trade cryptocurrencies, you should have at least part of your savings in stablecoins.