You're conflating some things. The reason that people have the idea that "unless you get paid to do something it isn’t worthwhile" is because getting paid for

You're conflating some things. The reason that people have the idea that "unless you get paid to do something it isn’t worthwhile" is because getting paid for something is reasonable evidence that you're creating value for others. That's important to do if you will be consuming the value created by others. Children raised without that feedback loop can easily be not so functional, in that will focus on serving themselves, not others. If you have enough money to fund things like socially beneficial research, then you should just fund that. The MacArthur Genius Grants are a good example of that. There's no particular reason to think that your particular children are the best ones to be doing that, especially if they've been raised in an environment where their wealth has let them avoid serving others.