Sourcing When Supplier is Known and Requestions Aren't Grouped

TLDR: what additional benefit does the sourcing to PO process have (if any) if supplier is known and requisitions aren't merged.

In my organization currently:

(1) we don't allow Requestors to order products from different suppliers in a single requestion;

(2) we don't allow Requestors to buy items that aren't already associated with a specific supplier;

(3) we don't allow Buyers to merge different Requisitions into a single PO

Therefore, we just manually expedite each Requisition to A PO.

Is there any reason to use the delivered Sourcing process (which is the normal way of creating POs)? Does it do something else?