There is not an option to use your 2019 income to claim stimulus payments. The option that you are referring to is for people who did not have enough earned income in 2020 to qualify for the Earned Income Credit.
That happened to many people who were collecting unemployment instead of wages in 2020. Unemployment is not earned income, so they did not qualify for the earned income limit with their 2020 income. The government gives them an opportunity to file using their 2019 earned income if that gives them a better result on their 2020 taxes.
