Agreed. All medical treatments are about balancing risks. Whenever you take any surgery (for example), the meaningful risk of immediate death is balanced again

Agreed. All medical treatments are about balancing risks. Whenever you take any surgery (for example), the meaningful risk of immediate death is balanced against the benefit of better quality of life later. If you measure the impact of medical treatments only on the day they are taken, you'll only find evidence that a bunch of people have died who wouldn't have otherwise died on that day. You can't then observe the benefit until some time has passed.