You basically politely ask AWS if they will refund you when you're DDoSed and hope the attack is apparent enough to pass their threshold.
They were generous enough, but at the expense of uncertainty + you needing to play an active role in getting them to pay your bill. Depending on what sort of service you run, it may be a constant ordeal.
After getting some large CloudFront bills taken care of, I left and wondered what sort of person had the stomach it.
The last three jobs I had at smaller companies definitely had someone at least look at my Github portfolio which is quite extensive. I know because the person who looked told me once they were my coworker.
They said it was immediately obvious I knew what I was doing. Nice to have that edge over people who have nothing to show.