I think you're still stuck on W-2 employees (which is a pretty large and common case, I admit, and I'd love to see that simplified).
You will always need accounting for businesses (IMO).
Suppose you ran a lemonade stand. You bought some equipment, some raw materials, you used some utilities, you used some space, you bought a banner and some flyers to advertise your stand, you hired a lawyer to help set it up, you bought a business license, you bought cups and napkins, you took in some receipts. Let's presume you turned a profit.
On what figure should you pay taxes? The gross receipts (every dollar you took in)? Or just the profit (receipts minus expenses)?
And that's just a lemonade stand; imagine the complexity of a larger scale business...