they have to spend it anyways – but need to last the 10 years. If they spent it all because they assumed a higher risk tolerance immediately - they would not last the 10 years. If they spent it closer to 10 years - they are good.
and they do not have all the money to hand immediately - they will receive the money over time - and possibly completely only closer to the 10 year mark.
So they need to be careful about how they spend the money - otherwise they will run out.