The website and app don’t contain any ads, no donation links, no way of making money. No data is collected, so there is no opportunity to make money there either.
So, “Why create it?”
The simple answer is that this app was created by a lone student with two nationalities, and tax laws are complicated. Combined, this means that making money off of the app would mean a lot of effort, and the payoff would be low. If the app goes viral, which I don’t expect, I may include some unobtrusive ads, but they would be out of the way.
Data privacy is important to me so I would do my best to ensure that whatever happens in the future, no data is collected other than what is absolutely necessary.