These are good questions to evaluate, as the author points out there is no "right" way to do this. Making sure your idea solves real customers problems that align with your personal values and goals makes sense to me. Another tool I like to use in this phase is the Business Model Canvas, it makes you think about the business side, giving you a clear overview of your idea and the avenues to turn it into a real business https://en.wikipedia.org/wiki/Business_Model_Canvas