I only can see the following advantages:
1. The network traffic will be descentralized in each region and you will not have to care abuot AV data in your WAN.
2. Administration can be totally descentralized if its a need for your organization.
3. Not subjected to a single point of failure. A single ePO server down will affect only that region instead of affecting all of your environment.
However, as you should already know, having multiple ePO servers is hard to keep policies/exclusions standard in all of your environment and it will require much more work from your side. Multiple ePOs means multiple databases to maintain, multiple places to assign policies, to montior, etc. While there are a couple of resources that can help you to manage multiple ePO servers (like Policy/Task Sharing, Data Rollup Task/Reports, etc), personally I'd prefer having only one ePO server (in cluster, if a single point of failure is a concern) instead of implementing a couple of them.
BTW, don't forget to backup your ePO on regular basis after you setup them (https://kc.mcafee.com/corporate/index?page=content&id=KB66616&actp=search&viewlo cale=en_US&searchid=1335187740712).