The pains
Cost tools create a parallel workflow
Yet another dashboard, yet another approval queue, yet another disconnected audit trail your platform team has to chase.
Automation that fights IaC
A vendor "rightsizes" an instance that Terraform recreates on the next apply, and the savings number stays put on the marketing slide.
No way to integrate cost with your incident workflow
When a cost spike happens at 3 AM it lands in someone's email, not in the on-call paging channel.