I am unable to locate any service level information regarding My Alfresco and am uncertain as to whether I should be using it.
If you are using my.alfresco.com, then that is the cloud-based offering of Alfresco, which always runs based on the Enterprise-Edition of Alfresco. Though that is not of interest to you, since your cloud subscription already covers any licensing for usage of the platform.
Whether you "should" be using it is a matter of your specific use case and requirements regarding data storage location / privacy / compliance etc.
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