You won't get any dividends from investing in stable coin. For me it is just another way of how to stay out of the market. If there is a rally I prefer to stay out and selling my cryptos for stable coins and when things are getting better, buy more altcoins.
You will have no chance to buy back your altcoin again, imagine crypto can go to the moon instantly, when it was going to the moon and you will need more fresh money and that means if you must put more money to buy back your portfolios again.