In the quiet times, I ask myself these questions and get sheepish, embarrassed answers. When you can give reasoned, confident answers on hard, painful questions about your future business rather than current tech demo, then your project has a shot at life.
I have an amazeballs tech demo for my side project. It is scoped way too huge. Heroics and not knowing what I was signing up for got it to where it is today.
Honestly, if I were to do it again, my first features would have been user management and payment processing. I wish I could take users and have them pay me as soon as they saw value in my growing hobby project. But I can't because I didn't prioritize getting users and using their subscriptions to fund my work. I have a ton of neat features and no users, argh!!