There are hundreds of other people building useful apps on here, and nobody will ever look at them.
Nostr is mostly a social medium, so your follow count (or the follow count of the people that boost your stuff) is the main thing that determines your app's user numbers. People have to know the app exists and trust you enough to try it out, both of which are nearly impossible, unless they know you _before_ you build.
Vibe-coding actually doubles-down on this effect, as there's quickly a flood of apps and users have to select by brand. Vibe-coding makes apps a commodity, so people look for names they recognize, like when buying ketchup at the grocery store. Since all of the apps are open-source, you can't even compete by offering a cheaper price.