What is the use of Expense AP Accrual

Hello experts

I'm in r12.1.3 and today we use PO with no receipts and 2 way match.

We are going to change to 3 way match and use receiving. We don't use Requisition, just standard PO's.

All of them are expense PO. We don't have inventory nor inventory items. All ours PO are destination Expense.

Is this change going to need accounting? Right now we don't have any type of accounting with PO's.

But what happens with this change? Do we need accounting now because we are going to do receipts?

Is the Expense AP Accrual going to be usel? will have entries in GL?