CloudWatch is a monitoring service that AWS offers publicly. It is different from the monitoring service that AWS services use internally.
source: was on an AWS service team for several years
source: was on an AWS service team for several years
On one hand, one can design a service with minimum dependencies to survive other services' outages, but that means duplication of effort and increased cost, as well as slower delivery of features. Or one can focus on adding value.
It seems though, from the update, that CloudWatch is going to have some sort of caching for most recent data.
But good to know! Thanks!