Is purchase receipt really important?

It's quite important for me as a business owner. With receipt, I can record proof of transaction, manage cashflow, etc.

As a customer, yes I need those receipt for my cashflow

Definitely, purchase receipts are important as business owners / self employed. They need to keep records of them for tax deductibles, which may adds up to an significant amount. Check out this app here https://www.producthunt.com/prod... which helps to keep track of receipts and make tax season a breeze. Let me know what you think!