But it's not always clear what is "green"? For example, New Users going up can be a good thing but New Users going up by a lot can represent a fraud attack. Metrics always require some interpretation to provide value which is why we have dashboards instead of alerts.
There are some metrics that are binary good/bad and I agree that in those cases you should just have an alert.
There are some metrics that are binary good/bad and I agree that in those cases you should just have an alert.