Why do flippers not use their own money if they have it?

[Abigail J Steinert]

I keep hearing on the podcast that house flippers always tend to use other lenders, hard money, etc... Even in J Scott's book on Flipping Houses says that they use investors and don't really use their own money.

What I want to know is why. I would think you would want to use lenders in the beginning but as soon as you have enough capital from successful flips, you use your own money and reinvest.