Segment employee here. Our Kafka runbook looks 100X cleaner after this tool was rolled out by Ben and folks. One of my favorite parts is how it makes dangerous things harder :)
Yes, we looked at Terraform to manage our topics. We are big Terraform user to manage our infrastructure. We mostly didn't go that way because we didn't want to have to manage the Terraform state. We also wanted the tool to be extensible and writing custom TF providers can sometime be tricky.