I'm not sure if you meant it this way, but your tone makes it seem like the parent just needs to "read the docs".
Unfortunately for all of us, your solution doesn't work, per the huge disclaimer on the page that says those alerts can be days late. You can rack up an almost unlimited $ bill in hours.
As a former victim to the same issue as OP, I am furious every time I see a Googler promote that as a solution.
In our case, we racked up a $10000 bill on BigQuery in ~6 hours, when a job was failing and auto-retrying.
We had set up every alert correctly and our reaction time was about 5 minutes (about $100 of usage, no big deal). So how did we get a $5000 bill? Google's alert was 6 hours late (according to them, this was root-caused to us, because we were submitting jobs continuously). They pointed to their TOS and said they don't guarantee on-time delivery of the alert.
I had to write up a blog post with fancy graphs and prepare it for social media before they finally agreed to eat the bill.
Unfortunately for all of us, your solution doesn't work, per the huge disclaimer on the page that says those alerts can be days late. You can rack up an almost unlimited $ bill in hours.