I'm a bit baffled about what interest this would hold for the HN audience. Does it solve unusual technical challenges? Is it open source?

Seems to be no to both questions. Just another commercial site, like many others. No shade, but baffling.

IMO: if your goal is to attract users or to make money, you have too many strong free competitors to be using ads like this, especially if your audience read Hacker News. It's not the right business model. Any amount of time spent making these ads 'smoother' is better spent on the product, because you won't earn enough ad revenue to make it worth it.

If you need revenue to pay for hosting, you'd be better off making it open source or self-hostable.

If your goal is getting feedback, you have to recognise that people are doing it for you, not for them. Don't make them pay you to do it.