AWS (along with the vast majority of B2B services in the software development industry) is good because it allows you to focus on building your product or business without needing to worry about managing servers nearly as much.

The problems here are no different than using SaaS anywhere else in a business, you can also run all your sales tracking through excel, it's just that once you have more than a few people doing sales that becomes a major bottleneck the same way not having an easier to manage infrastructure system.