If your app is largely just a wrapper around a neat prompt, it means I can just go and copy the prompt and use it myself and save the fees on your app.
Your app has to really be a valuable UX wrap over the calls in that case, or catering to a nontechnical audience.
There is space on the market for such apps, too. Lots of space, in fact, as the idea of making software tools instead of toys seems to be forgotten. "Bicycle for the mind" got stolen some years ago, and it's time to get it back.
And frankly, an app that's "largely just a wrapper around a neat prompt", is something I consider to fall somewhere between Fischer-Price copycat toy and a direct scam. It's definitely not a tool empowering people, if it can be replaced with "paste this into ChatGPT config" (or "paste this into this more configurable bring-your-own-key frontend for ChatGPT").
I agree. My point is that as a business the only moat they'd have is to not do client side requests, in order to hide the prompt.