I think it depends on the use case. It works well for a short template like the one that was used in support, but I think for longer templates like in Marketplace it wouldn’t be that helpful if the template disappeared once you enter the first character. For me, the text in the body in marketplace topics is a good compromise between a placeholder that disappears when you start typing and a template with fixed fields like the form-templates offer.
Though I wonder if telling users to search every time they create a topic makes a difference. Do people really read that every time they create a topic?
Telling users to search is something I’d more likely tell them the first times they are posting. For example, in the jit composer message shown on the first few topics you create. “Please search” is kind of like “please chose a meaningful title”.