Answer:
I'd say all of them have somewhat of a profound amount of viability and usefulness when it comes to teachers trying to find appropriate content, but "Can be used across subject areas" is not distinct enough, and is to broad/unclear, since quite obviously if teachers are looking for content for there students they will be looking for apps that are used for teaching certain subject areas. Every app used for teaching will be used for certain subject areas, so stating that statement is a mere waste of time & space. Where as "This app is not available in the Chrome Web Store" is pretty helpful to know, because knowing if an app is available or not is really important. "Helped my struggling students really understand the concept of color harmony." may be helpful if you are trying to find an app that correlates to science as the concept of color harmony is science. And "Doesn’t have much of a learning curve" shows that the app can be used long-term and is informative.