I think you are discounting the mental, physical and social toll of being locked up for 10 years. Without autonomy, without privacy, without access to your loved ones (some of whom might die, and the rest will likely have irreparably damaged relationship after), treated as a bad person, surrounded by criminals. It's not "you get 400M for aging 10 years", or for dying ten years younger; I might take those deals. It's spending those 10 years in a prison, and dealing with the consequences of that after.
Yeah but it was voluntary. He was locked up on contempt for refusing to give the location of the remaining gold coins for 2 years and only stayed in jail for 10 years because he kept refusing. They let him out after 10 years because he was "unlikely to ever offer an answer". It sounds like his mental process was slightly different than what most people in this thread are arguing.