Quality of Health
The biggest question regarding Cam Newton and arguably the reason that the Panthers released him in the first place is his health-related absences from football. He missed the entire 2019 season on the injured reserve.
However, after having surgery, I believe that Cam is in the best health he has been in, in the last couple of seasons. That would be a huge benefit to the New Orleans Saints if they were willing to take the gamble.
As a backup, it would also give Newton more time to prepare to become a starting quarterback — similar to the same situation with Teddy Bridgewater. This time though, he would be preparing to take over the New Orleans Saints instead of leaving.