Its more of a usecase for large platform teams that want to automate and enable hundreds of teams with thousands of disparate cloud resources.
You can have a small bit of terraform for crossplane then crossplane for the 99% of the other resources
If your only tool is a hammer then every problem looks like a nail. It's absurd how anyone would think it's a good idea to implement their IaC infrastructure, the one think you want and need to be bootstrapable, to require a full blown K8s cluster already up-and-running with custom operators perfectly configured and working flawlessly. Madness.