None. It would be incomparably more useful if the funds and efforts spent on the training of several dozen Olympians were spent on the development of mass sports.
Of course, politicians who speculate on falsely understood patriotism and TV channels that receive income from advertising have their profit. Sports officials win the most. But in my opinion, calling it a benefit for the country and its inhabitants is completely wrong.
Depends on the state. For small countries, the victory of an athlete is primarily an advertisement for the country. "Look, there is some kind of n-land with a steep bobsled, let's at least look for it on the map, maybe there is something else interesting besides bobsleigh." For the powers, there is no direct benefit from victories at the Olympics (as well as world championships and other international competitions), but there is an indirect benefit through advertising of sports in the country. "Oh, how cool ours are in hockey / figure skating / skiing, they can take the child to the section, let him learn"
First, where do victories come from? This is the result of many years , and more often many decades, efforts of many specialists , who also need to be educated, aimed at broad masses of children and adolescents . To cope with such a crowd requires an extensive sports infrastructure , and to achieve international results, it must be state-of-the-art.
What are the benefits of these actions, expressed through world-class awards?
Victories increase the prestige of the state, the morale of the population rises, there is a reason to be proud of your country. Although recently the Olympiad has been rather a bone of contention between countries, this event is becoming an arena of struggle between states not just at the sports competitive level, but already at the political level, which is generally regrettable
What preparatory activities are in progress?