The "difference between killing and letting die" has quite a lot of importance in "real life". One example that come to mind are the intense discussions in some

The "difference between killing and letting die" has quite a lot of importance in "real life". One example that come to mind are the intense discussions in some countries about the possible decision to shoot down a highjacked plane (killing some to save many). It's official policy in the US, but the German Supreme Court considered it unconstitutional when they examined a law intended to codify it. Another example is the discussion about the algorithm's decisions in kill some/save many scenarios in autonomous driving. In philosophy, the Trolley Problem and its many variants are about exactly these sort of problems. I wouldn't say that philosophy has given any "answers" to these problems, but the debate (and politics/law/software) would certainly be different, or just not happening, without these efforts. Effective Altruism is another well-known concept that can be called "applied philosophy". As are "responsibility to protect" ("do world power have a duty to protect people in other countries from, for example, genocide"), and anything in economics and criminal law that requires some sort of common understanding of what is "just".