It's really annoying how user-hostile the cloud providers are. Why do cloud providers not by-default alert you when your bill increases dramatically? Why is it your personal responsibility to manually configure an obtuse billing alert system?
My water utility will call me when my water usage spikes. That happened when I had a burst pipe but I'm not sure they're consistent with this so wouldn't count it as firmly as with the mobile carrier.
Besides, not providing an alert by default is still user-hostile, even if other services don't provide them.