The accounting method you choose to use can determine how you show a profit in a given year. This directly affects your business income taxes, and it may also impact whether you are able to obtain a loan or raise investments. Unlike other accounting choices, you can't choose what's best from year to year — you have to make a choice and stick with it for the long term.
The accrual concept of accounting is the only method that is recognized within GAAP principles, the generally.