> ...what do you think they would materially gain from it?
$100K at age 20 can become $1.6M by age 60, per the rule of 72, if invested in a diversified stock index with 7% total return. At age 60, the 4% safe-withdrawal rule says that $1.6M might provide $64K/year indefinitely.
So, they could gain a hell of a lot from $100K when young. The trick is saving/investing/time.