I took this as a bare minimum price per user for the project to be worth your time (i.e. better pay than your day job) — maybe that could be communicated more clearly?
Speak of the devil, as you posted this I updated the messaging to say exactly this! Thanks for the feedback.
This is something this tool can be useful for: a lower bound estimate. But as side businesses bear uncertainties, a risk averse person should probably charge more than the given estimate.