If you use the standard Email Action, You don't need to pre-define the
value of ToAddress field whereas if you created a custom case object
specific Email Action, You need to Pre-define the value of ToAddress
The below action will be automatically enabled when you enable email-to-case in the org. To Recipients field is already pre-defined.
I am facing the same problem. I need to retrieve the Id and MasterLabel of all the Service Presence Status. In addition, I am developing an application and I need to deploy it in different orgs, some of them having Omni activated and some of them not. I got a "Invalid type: Schema.ServicePresenceStatus" when pushing with SFDX on an Org without Omni Channel ...