Old people are the most experienced (not all) people, I believe they are doing it through experience. Throughout ages, though precious metals are not as profitable at bitcoin and other leading altcoins at the moment, but they’ve proven it to be less risky, the more tangible it is for them the more security they feel about it and besides these metals has not failed yet throughout the years. Some old people, i dont know if it can be called ignorance but they dont want to try something unsure for them but they would rather stick to the one they’ve already known.