Why should Electroneum be worth anything?

Electroneum created a lot of hype pre ICO and managed to garner a lot of attention from the cryptographic community. Their objective is to have financial inclusion by having everyone mine through their mobile app. This app was launched initially 3 or so months ago. Users have been complaining ever since that the app doesn't really mine Electroneum as the power required would really melt your phone.

As the saying goes, 'There is no smoke without a fire', there could be some credibility to these allegations. It maybe some kind of a data entry through which Electroneum team is only giving away its own Electroneum to its so called miners using the app. What is shown as a mining app may really be just an app - a UI. So while these transactions are shown as being recorded on the blockchain, they really might be. However that doesn't absolve them from the fact that this app may not be mining anything at all.

Why should an app that lets people supposedly mine a worthless currency be worth anything at all? By that logic, I could make an app tomorrow which mines 'cryptogemcoin'. Would that make my coin valuable?