If anyone wants to see some of the negative effects of a persistent 'social score' that affects real life I recommend this Black Mirror episode: https://en.wikipedia.org/wiki/Nosedive .
Yea that episode the "credit" was objective based on random people's opinions. According to the article, they claim that you have to not pay fines, or smoke on a train to ruin your social credit.
Once a system like this is in place it will be abused. It's practically designed to be abused. Where is the accountability?