I had (have?) an Azure account through my university account and while I agree that Azure services such as Container Service are (in my not so humble opinion) ridiculously overpriced but the fact it I never entered payment details to use my USD 100 of free credit on Azure. I effectively have spending cap of zero dollars.
I thought I was the only one who thought pricing on Azure seemed rather high for what you get.
But I also have free credit I can use each month, which offsets the cost to "normal" levels, but can't imagine being a business and opting to pay for Azure services by choice, unless they provide something no one else does.