The advantages of cloud services vs on-premises infrastructure and solutions are numerous. As a starter, you avoid huge capital expenditures and the risk that you under or overprovision the necessary hardware. Also, there would be no need to adjust your organizational structure just to make sure that you have teams who can manage the required on-prem hardware, software, networking, security, etc.
With AWS services you can cut the capital expenditures and replace them with much more effective and reduced operational expenditures as you pay only for what you use, your solutions can scale both vertically and horizontally depending on the workloads in a matter of minutes. Also, you can take advantage of the shared responsibility model and fully managed services, where AWS-as-a-service provider is taking care of a great deal of the things (security, maintenance, patching, etc.), so your organization can focus on mission critical activities.