Credit ratings are benchmarks for institutional investors to price credit risk exposures. In the modern context they are money-proxies, however some ratings are not valid money-proxies.

Credit scores (or rankings, or indices) are quality benchmarks used in lending to individuals and small borrowers. 

A score becomes a rating when it has a monotonic mapping to a probability of default or perfect coincidence. Only then can it be legitimately used as a money proxy.

If you are interested in understanding more about the informational design elements of Clean Fintech ratings, see What Is A Rating?