Answer:
The cash flow is defined as the total addition of net income and non cash expenses such as depreciation.
The Cash Flow is a better comprehensive measure of firms profits due to the fact that it stands for the real income gained by the company from its activities.
It's worthy to note that a firm can attain its operations only via real asset such as cash and not by using the net income.
Therefore, this brings clarity on why the knowledge about net cash flow is of extreme value when viewed against the net income.