Bandwidth on GCP (and AWS and most of the other providers) is really, really, really expensive. $0.12 per gigabyte, upwards of $0.19 per gigabyte for Asia. Paying $0.12 for every time you send an Ubuntu ISO is crazy. A bored script kiddie could just run up your bandwidth costs to thousands of dollars just for the hell of it. A DDoS could make you declare bankruptcy.
I have a server with OVH I can theoretically push 100+TB per month through and only pay $100. I get DDoS protection included. It may not be perfect DDoS, but it's not the $6000/mo I'd need to pay for Cloudflare to get the same thing with GCP (I need wildcards), plus the $0.12 per GB for anything not cached by them.
I know from people in the industry that they pay less than a cent per GB. Google, if you want to differentiate your cloud services, start charging better prices for bandwidth and do something about DDoS (project shield should be baked into your offerings). $0.02 would be reasonable and you'll still make a profit. That goes for all the other "great value" cloud services that are actually very expensive for anybody doing work that actually needs bandwidth on the internet.