What are the main benefits of shared computer activation for office 365?

The main outcome of SCA for Office 365 ProPlus is that it gives more choice and flexibility. SCA allows you to take advantage of existing Office 365 licensing investments when deploying to the cloud.

You can make a deployment choice between on-premises, on Microsoft Azure, or any authorized Service Providers’ shared datacenter to help lower cloud infrastructure costs by letting any qualified cloud partner that is an Authorized SCA Partner deploy your eligible Office 365 licenses to your chosen cloud infrastructure solution.