A good use of investor money is when you have a proven and controllable conversion from signups -> paying customers. For example if you need $200 averagely to

A good use of investor money is when you have a proven and controllable conversion from signups -> paying customers. For example if you need $200 averagely to acquire a customer and the LifeTime value of the customer is $500 over a 10 months timespan. With a positive conversion, you can scale very aggressively with almost no risk, whereas if you re-invest your profit, it will take much longer to reach the same point. If you are in a competitive space, you especially might benefit from investor money.