I think it’s perfectly reasonable to make something useless for fun, it’s an interesting idea. But what I’d like to understand is why there are so many of the same thing. I know I’ve seen this exact idea multiple times on HN. It’s funny the first time, but once it’s done once and the novelty is gone (which is almost immediately), what’s the point of another and another and another?
URL Shortener is still one of the most popular System Design questions, building this project is a great way to have some experience / understanding of it, for example.