Answer & Explanation
No.
If you fail to plan, you plan to fail. Cash budget can be considered as a plan what you want to achieve regarding the sources and uses of your cash. Thus, it will help you as a manager to check if you are on the right track, if you were able to achieve the plan (budget). Therefore, i do not agree that preparing a budget is a waste of time because as mentioned above, a cash budget is very useful in achieving your desired objective(profit) for the business.
One should not agree with the manager.
The reason for this is that a cash budget can help with the timing of cash flows, and helps ensure that the company will have cash on hand when needed as bills come due. A cash budget can help avoid excess spending, avoid cash shortfalls which lead to an added cost of borrowing, and help ensure an acceptable cash balance, which can aid in profit maximization.