Thanks @downey. You’re correct. The use case is for a topic calling for consistent (templated) responses that doesn’t itself merit a new category and doesn’t rely on respondents to manually select the template.
I realize this is an edge case, but after running into it a few times, I thought I’d make the feature request. Perhaps if a few other Discourse users find themselves wishing they could provide an ad-hoc template for a specific topic and find their way here, there will be more use cases for the feature. In the meantime, we’ll continue to use the workaround: asking people to provide specific details in their responses within the original post and hope they read it. 