You might be wondering why would anyone want to earn anything other than ADA?..
In many countries Staking Rewards are taxed as Income so you need to pay tax at the value of the token at the time you received it.
Unfortunately if the price drops by a lot you could pay more tax than the token is now worth!
If there was an option to get paid some of your staking reward in a native token you could receive the percentage you will need to pay in tax with a stable coin and the rest in ADA.
People have different tax requirements so it would be necessary to set a personal balance for staking rewards payouts between ADA and stable coins.