I will share a market research perspective in that in your pitch, you are outlining the total addressable market by virtue of what problem would your product or service solves and what current product(s) or service(s) would your solution replace. What is the current value of that market? How many competitors exist in that market? Your ability to get a piece of that market (with a good execution team) is the size of the prize for the investment. What primary research (whether in-market test, purchase simulation, focus groups, surveys, etc.) have you conducted to examine potential users' interest in your solution? How do these figures enter into your projected financial models for adoption? I do agree with most of what what has been said regarding the "value" of just an idea, but the due diligence around the idea looks like what I just described.
Many consumer product companies build volume estimation models to gauge market response and revenue on a new product prior to launch. Startups (especially tech startups) can be too unpredictable to build a precise mathematical model on exactly how many units will sell based on marketing spend, but you can use some similar analytic tools to mitigate some risk.