I don't think that's necessarily true.
You can be cashflow positive and still benefit from having a larger pool of cash to throw around, particularly in any situation involving hardware manufacturing.
If you tell your investors "our limiting factor is how fast we can spend to deliver on additional requirements for these new customers", then it can both be true that you're not going to miss payroll for 5 years no matter what happens tomorrow and more cash would be beneficial.
No, it's not necessarily true but it is a well trod path.