Aren't you afraid of running such service on Google infrastructure and getting the ban hammer from Google?

No I am definitely not afraid of that, based on several factors: knowing what really happens in practice having used GCP since 2014; my company being in the highest tier of Google’s startup program; I know many people who work at Google (eg numerous of my past PhD students). Of course my risk analysis parameters may be completely different than yours. On a purely technical level, GCP is a good quality product.

Does it even matter to GCloud (a paid service) if I use 100% of the GPU for Deep Learning or for mining? They operate on profit either way.

They also care because in practice such use is often done by attackers unbeknownst to the person paying for the resources. That would much rather make the person paying aware ASAP of such usage, rather than have them be on the hook for a large bill at the end of the month. Google does have a complicated process to allow cryptomining on their infrastructure. They also flag all kinds of other suspicious activity, eg once somebody was launching DOS attack from cocalc on “the country of Turkey” and that got some of cocalc shutoff immediately.

It does, I think, for the same reason GPU manufactories segment GPUs for gaming and for Deep Learning.