Even if a service actually has a status page, it’s rarely updated with the current information. You might be seeing issues on your account while the status page continues to show all green. When the service is failing, you may need to help their support troubleshoot. That’s why all of their notifications include a full transcript of the HTTP request and response.
Unresponsive services aren’t the only issue. If a service is running slowly or returning non-success status codes, that can be just as bad or worse. To make sure you know the whole picture they monitor performance, HTTP errors and uptime.