An advertised annuity jackpot is a stream of payments over time. A cash option is a smaller lump sum based on the amount available to fund that stream. They are different payout bases, so compare like with like.
Powerball’s two choices
Powerball explains that an annuity winner receives one immediate payment followed by 29 annual payments that grow by 5% each year. Its cash value and advertised annuity are estimates until final sales and other inputs are known. The Powerball profile identifies the researched prize basis.
Other lotteries may pay cash only, offer a choice, or use different rules. Check the payout type and source on each lottery profile before comparing headline amounts.