What's the rationale for not enabling fixed plans in the Rest API?

Hello,

We are currently evaluating what services to use for a client’s infrastructure. The initial plan was to use AWS + Redis Cloud via Terraform, but it seems like such a solution only works if we would opt for the Flexible plan. However, the flexible plan is a bit overkill for our use cases. Please note that it would be preferable if the complete Redis solution is generated and managed by Terraform.

When tinkering with the terraform provider and generating subscriptions etc, I ran into the realisation that Redis Cloud fixed plans are not available via the API and thus not in a Terraform infratructure solution. What is the reasoning behind this?