What is this kind of sh1t!? Why do people put their software on a platform where you don't know what it's going to cost upfront? Maybe I don't understand. Mayb

What is this kind of sh1t!? Why do people put their software on a platform where you don't know what it's going to cost upfront? Maybe I don't understand. Maybe there are legitimate use cases for AWS and other 'vague clouds'. And it's not only these kinds of bills you get, but I also heard one even has to pay to get your own stuff off of these platforms. What's wrong with good old webhosting (in whatever shape, size or form)? I understand there are use cases - probably for big big apps - that will benefit from cloud hosting, but that can't be for every project or business. Right? Please enlighten me.