There is and every business should be that detailed. It is #1 for transparency..... the public deserves to know where every single penny is going. It's hard to justify costs for something if you don't know where or why the money is being spent. #2 it is for accountability. You should know if your personnel is spending the money wisely. Are they getting the best bang for their buck? Are they WAY overspending for items that can be easily purchased for way cheaper elsewhere. For instance, if a coach was buying helmet snaps from his buddy that is a supplier, and the cost is 4x the cost it should be, I should be able to find that out and tell that employee he needs to purchase said equipment elsewhere. Also, if there isn't the meticulous detail involved, it's pretty easy to skim from the pot, or adjust the numbers in your benefit.....especially if nobody is checking in on you #3 it is for cost analysis. I know things in schools and in business cost different amounts. For instance, Social Studies is generally going to be one of your cheaper departments to run (to use your example), but if you find out that Social Studies is spending more on educating students with an IEP than the Science Department (typically the most expensive of the "core academic subjects" you need to find out why). You also need to find out through your analysis if programs/products you are using, whether in athletics, academics, or general upkeep, are worth the cost. In other words, can you justify spending X amount of dollars for what you get in return?
To say there is no benefit to this kind of detail is one of the many reasons our education system is broken.