I think in some cases you could provide value even by merit of reaching big adoption and nothing else.
Let's say that you come across a super nice frontend that someone built that lets you use GPT-3 to generate names for kittens. And you love kittens and you have a lot of kittens all the time and so you use this tool a lot, and so does a bunch of other people on the Internet that loves kittens also.
3 days later five new services pop up which do more or less the same thing. Maybe the UIs are slightly different, maybe the prompts they use differ a little bit. But for all intents and purposes, they are the same.
Yet, the one that spread the furthest first might remain in the top position, because it became familiar to a lot of people and it does what they need and it continues to provide sufficient value that most people stick to it, and these faithful users also continue to tell other people about that one.
In that case, it could remain popular for years, even if the service does not keep any data and most of the value comes from the easily cloned prompt.
I don't think it's a fad but startups will definitely need to find ways of adding value on top of just "helping with the prompt" since that part is indeed easy to reproduce. To be fair, I probably haven't reached that bar with eli5.gg but I have some ideas on how it could be improved.
