Their main practical function is to serve as the steering board of the National Science Foundation. They meet a few times a year to vote on major decisions, e.g

Their main practical function is to serve as the steering board of the National Science Foundation. They meet a few times a year to vote on major decisions, e.g. which grant initiatives will go forward or be axed, appointments of program managers, budget allocations between research areas, changes in strategic direction, that kind of thing.