The difference here is how it's used: If you have a "bad" social credit score in China you can't participate in some activities, right up to buying a domestic train or airline ticket. Possibly because your online writings have angered somebody working for their Internet Police. Or you have expressed an unpopular political opinion. Or you're a Uyghur.
It's a social credit score which gauges your compliance with societal and police-state defined norms.
And again, the US government does care about dissent and goes to great lengths to build files on what it considers potentially subversive forces that are essentially political dissidents. The same controlling impulses are there. And since the scaffolding is all there, the only things safeguarding against a dystopia are, firstly, the clear-headed and astute attention against various soft forms of social control, secondly the maintenance of decentralization as a virtue, and lastly the robust exercise of checks and balances that are nominally provided institutionally, and not, as your answer seems to imply, the intricacies of how certain scores are constructed.
and how relevant is that to the life of the average American citizen?
In a sense, the American apparatus is significantly more advanced. You don't even need a scary government and a social credit or a staunch party line. You simply dangle the carrot of free political speech around, let people run around with their signs on the street on occasion and they're perfectly content with their lot.
Being homeless and jobless is a strictly financial problem?