Account assignment on SRM

I have a question about account assignment : I had seen that we need to define the account assignment categories and assign an account assignment field to the account assignment category.

SPRO > SAP Reference IMG > Supplier relationship Management > SRM server > Cross Application Basic Settings > Account assignment > Define Account assignment categories

In my scenario the flow is Contract –> Requisition –> PO creation on SRM and Contract and PO replication to the backend system and the following process will continue on the backend system. What is not clear to me is that in my scenario will I have to activate the above part?

Thanks in advance,

#Bill J.