A major benefit of k8s that is usually massively overlooked is it's RBAC system and specifically how nice a namespace per team or per service model can be.
It's probably not something a lot of people think about until they need to handle compliance and controls for SOC II and friends but as someone that has done many such audits it's always been great to be able to simply show exactly how can do what on which service in which environment in a completely declarative way.
You can try achieve the same things with AWS IAM but the sheer complexity of it makes it hard to sell to auditors which have come to associate "Terraform == god powers" and convincing them that you have locked it down enough to safely hand to app teams is... tiresome.
