Old money are mostly out of the rat race, more distant from the need of self-marketing, and usually with better education and taste (in fact, it's almost proverbial that old money have better taste than the "nouveaux rich").

All kinds of writers, artists, scientists etc were once from that group.

So it's more probable to listen to something interesting from an old money millionaire who inherited wealth, than from a self-made one (which would tire you with self-promotion and gloating about their business acumen, bravado, and hardships they had to overcome).