Because some people here do exactly the same thing with aws/cloud. Not you but many here treat aws like it’s the thing you should use ‘because scaling and failover and omg 1 sec downtime’. And then the stories like OP showing that it is dangerous and my experience that most who do this are overpaying and could do with a hetzner server or, better even, a $5/mo vps, even if they do it right (which they are not, generally from all setups I have seen).
Obviously the billing mechanism (or, lack of control) is an issue but that doesn't negate the whole concept. They could (and should) easily fix this by implementing hard caps to activate if so required.
I agree with you though on the case by case.