The thing about ads is that you don’t need to click on them to work. You can’t click on billboards or newspaper ads either. Keep the product in mind is already most of what you want to achieve.
I haven’t advertised on SO, but the copy text on their advertising page doesn’t sound like they’re selling slots on a CTR basis. They seem to be well aware that clicks will be rare and are upfront about that. https://www.stackoverflowbusiness.com/advertise