If your fixed income (Social Security/pensions) doesn't cover your basic living expenses, an annuity can bridge that gap.
If you expect to live well into your 90s, an annuity protects you from the risk of running out of money in your final years.
Pros to pension annuities. 1. Annuities provide peace of mind. You get a guaranteed, regular income for life, whatever happens. 2. The Annuity Nightmare | BEST Wealth Management
If market volatility keeps you up at night, an annuity acts as "personal insurance" against a market crash. Red Flags & Risks Should I buy an annuity or use drawdown? - The Times
You lose control over your lump sum. Once you buy an immediate annuity, that money is generally gone—you can't withdraw it for emergencies, and there is often nothing left for your heirs when you pass away. When It Generally Makes Sense