When integrating SAP Subscription Billing and SAP Entitlement Management, the standard integration documentation at help.sap.com and at api.sap.com follows this route:
Was this choice a best practice that SAP is officially recommending, or rather just one option that SAP wanted to offer?
We have a possibility to use information from the ordering system to replicate subscriptions to SAP Subscription Billing independently of using the same set of information from the ordering system to replicate entitlements to SAP Entitlement Management. Both could be replicated from ERP without entitlement management entitlement objects being aware of the SAP Subscription Billing subscription objects.
So we are just weighing whether or not there's a reason for the design: subscriptions comes first; entitlements come second, and come from Subscription Billing rather than the ordering system.
This is the documentation I am referring to above.
indeed there are both the options to integrate the entitlements directly from the order management or triggered through the subscription.
The main difference is the life-cycle you want to bind the entitlements to.
If the order triggers the entitlement, it's likely more a one-time entitlement. You get it along with your order and it either has a fixed term or it stays forever/until used-up.
Triggered from the subscription, the live-cycle of the entitlements can be synchronized with the subscription. The standard integration content propagates subscription cancellations, extension, withdrawals over to the connected entitlements.
Hope this helps to chose the appropriate option for your use case.