Because if you finance your idea yourself you're going all in. You're basically putting your career at stake there. If you have family then that can be a very d

Because if you finance your idea yourself you're going all in. You're basically putting your career at stake there. If you have family then that can be a very difficult choice to make. The other reason is that if you have other people invested in it (the VCs) they will also try to help you through things like helping you get contacts etc. Also, even if you build an app that doesn't mean anything. You need to get some marketing campaign out and you need to make sure you don't violate any laws or regulations. You have to do all of this alone.