>Someone can just look at a screenshot of my aicodeprep app and just make one and make it look the same too.

To some extent. But without your codebase they will make different decisions in the back which will affect a myriad of factors. Some may actually be better than your app, others will end up adding tech debt or have performance impacts. And this isn't even to get into truly novel algorithms; sometimes just having the experience to make a scalable app with best practices can make all the difference.

Or the audience doesn't care and they take the cheaper app anyway. It's not always a happy ending.