I can see your point of view. Personally, if I find that my app is similar to an ongoing Show HN, I like to wait for an opening where I can respond with a plug

I can see your point of view. Personally, if I find that my app is similar to an ongoing Show HN, I like to wait for an opening where I can respond with a plug for my own app. I don't feel comfortable talking up my own app unprompted. Feels like making a big attention grabbing announcement at someone else's wedding.