Well, that's the essence of cash flow. Many highly profitable companies have gone out of business for cash flow reasons - not for lack of profitability.
Cash flow is like the blood that flows in our veins.
It's as simple as that. That is why happiness is positive cash flow. In fact, life does not exist without cash flow. In business, there are several uses for preparing cash flow projections or statements. In early-stage business situations, cash flow projections are needed to determine how much money is needed to start the venture.