Perhaps you are right that, being a new startup founder, asking these questions to yourself may not help a lot. But I have no easy way to know that. Only someone who is new and is currently evaluating his startup idea can give me that feedback. In fact, I would love to have that kind of feedback.
But from my limited sample size of interaction with 4-5 new founders, I think the framework I laid out helped them get at least some clarity. Maybe that was because I asked them questions, or maybe it was because of questions themselves.
I am evaluating my startup idea and the first question work well for me. There is a huge system around us constantly praising cool things, and its easy to get in to a trap of building something that is cool.
Personally, I stick with Color and AirBNB. Color (the original app) was the epitome of cool. They were building something different, were innovative but I found little value in their product. AirBNB (if you take away their immense success) is a generic idea which has done well thanks to fantastic execution. Color and AirBNB are on two extreme ends. I stick with Tim O' Reilly's work on stuff that matters call.
The second question is 'the question'. Whether there is market or not, I will only know after my product is out in open.
Your third question doesn't apply to someone who is in the evaluating idea stage. At this stage, you are leaving everything to jump in to your startup, so you obviously love it.
You might be able to tell whether there is a market for your product today.
Does your product have any competitors? Find people who are using your competitors' products. E-mail them this afternoon and see if they're interested in what you're building.
But from my limited sample size of interaction with 4-5 new founders, I think the framework I laid out helped them get at least some clarity. Maybe that was because I asked them questions, or maybe it was because of questions themselves.