you get different amounts of money coming in at different times (investors, loans, revenue from sales) and you have different amounts of money flowing out at di

you get different amounts of money coming in at different times (investors, loans, revenue from sales) and you have different amounts of money flowing out at different times (paying workers, paying for supplies, equipment...) double entry bookkeeping not only "checksums" these quantities for errors, but also gives you different snapshots of your business, how much money do you owe in the short term, how much in the long term, on average what's the profit margin, how much tax do you owe this year. other people can also look at your accounts and check up on random sample pieces of information to ensure it's not all made up. It creates a clear picture where the raw data is somewhat murky, which enhances trust on many levels.