Because it's literally a credit score, for debt and loans. It's entire purpose is to serve exactly the same function that credit scores function in any other country.
You're freaking out about its effect on a bunch of things it has zero effect on at all. Your entire concept of it comes from people that have maliciously lied to you about what something with a scary name like "(social) credit score" could be if it were completely and totally different to how the Chinese are ACTUALLY implementing it.
Read this thread: https://mobile.twitter.com/isgoodrum/status/975536363364696064?lang=en