Accounting is nothing but recording of business transactions and its meaningful presentation thereon. Accounting of business transactions helps in assessing the financial implications of business process, financial status as on particular date as well as estimating the future essential and nonessential business expenses.

More over there is statutory requirement even to maintain prescribed set of accounts also in compliance of standards and rules prescribed as well as pronounced by legislation and statutory bodies.

For ex; Companies Act, 2013 mandates maintenance of books of accounts and its regular audit thereon. Besides standards on accounting are also in place there for accounting and related issues. Similarly, Income Tax Act, 1961 requires some accounting policies as well as standards to be followed for computation of total taxable Income.
So adherence to these rules and standards is also a statutory requirements and hence necessary. Besides from business performance viewpoint it is necessary all the time.