Significance of tax audit

1. I am not quite sure what you are expecting when you use the word "significance" 
2. Income tax act expects the assessee to carry out tax audit u/s 44AB if the gross receipts during the year exceed Rs. 1 crore. 
3. Various expenses and income should be thoroughly verified and the same should be given in Form 3CB and 3CD. This form will ensure that no deviations had taken place with respect to income and no income left unaccounted from the tax point of view. 
4. Tax audit is to ensure that books of accounts are proper fro tax angle. In other words to say, by giving this report you make it a documentary acknowledgment of income tax by ensuring that no deviations had taken place from the tax angle. 
5. The above explanation is just a few points I have mentioned from the tax audit point of view. 
Please correct me if the above explanation has an alternative view.