Hi @AEM_rookie
Please follow the below URL to find details about why we need to migrate to cloud service and also the advantages , the architectural differences from on prem
https://experienceleague.adobe.com/docs/experience-manager-cloud-service/content/migration-journey/g...
https://www.coforge.com/blog/aem-onprem-vs-ams-aem-vs-aemaacs
https://www.emizentech.com/blog/migration-guide-to-aem-as-a-cloud-service.html
Please note the changes on
1)replication service
2)containerized author and publish tier which helps in autoscaling
3) Asset Compute Service
4) Identity management Service .
All are modularized and decoupled helps in improved performance and scalability