As the previous poster said: normal pensions are in a trust.
The recipient gets a guaranteed monthly payment and the pension fund is responsible for managing the underlying investments (in theory this includes responsibility for any losses). Pension funds are also insured by the Feds (again, in theory, if the pension fund runs into trouble, the Federal insurance kicks in to cover the loss). In other words: You still get your pension check.
On the other hand, lump sums aren't insured. The retirement cash is paid upfront to you and you assume all risks including investment losses.
People good at managing money (and I mean you really are good at it, not “I think I’m good”) might benefit by taking the lump sum. A good investor could theoretically get a better rate of return over time than the pension fund. BUT… that better return comes with risks… such as a market meltdown (like now) followed by a sudden need for cash (medical bills for example). Such a scenario could leave you short on funds early in retirement. In truth, this is or something similar is a more likely downside than bankruptcy of the formal pension fund.
Check with a good fiduciary financial advisor (not just some broker who’s trying to get a commission by selling you investments or annuities). They can help you evaluate your options and make the best choice for you.
In my own case, I'm pretty good managing money, but I still plan on taking the monthly pension when that time comes. I view it as a risk management issue. I'm already assuming certain risks by managing my 401K and after-tax savings. The monthly pension option and Social Security will add different risk profiles. Overall, that should minimize adverse impacts to my retirement income.