Ask HN: Is a separate CI tool for Terraform needed?

Why are people using Terraform Cloud? I may be missing something, but why can't terraform just be run in GitHub Actions? I feel that for 99% of companies, a terraform runner fundamentally only needs the following flow: 1. Run terraform plan on every PR 2. Run terraform apply on merge to master/main branch. 3. Handle of concurrency by queuing multiple applies together. 4. Terraform secrets can be handled using GitHub Secrets. I created a demo repository [0] and it seems to work just fine. What am I missing?