China's social credit score is centralized and not anonymous. So, there's not really much to compare.
An decentralized credit score would have you scored by your peers. An anonymized one would only be evaluable when you chose to use it.
Could it present some heretofore unimagined dystopian situation? Sure, but the question was whether there was an application, not whether it was a good idea to build it :)
Moreover, reputation systems aren't inherently dystopian (or all encompassing like a social credit score, ftm), or we wouldn't have the long standing real-world ones.
There are a website called https://www.17ce.com/, it's a speed test service, but their server mainly located in China (Of course, it's a Chinese website), so it can be used to test status of some GFW blocks.
That website tells me GitHub is fine, and that's all, I guess.
There are about 500 articles every week about China's "social credit score" dystopia, and you want to put that on the block chain?