Hi, @johnsev.
As @orangebucket mentioned, this specific endpoint is for devices created by a SmartApp which is different from an Edge driver (the base of @TAustin’s integration).
Only the device handler can issue a status change and that’s why using the API with the commands for something like Switch or SwitchLevel works, because it calls the corresponding capability handler.
For events of capabilities without commands in their definition, the driver must issue the event but the how depends on its configuration, that’s why it would be interesting to know if Todd’s integration also supports receiving status changes to reflect them on the SmartThings side.
In the case of Z-Wave and Zigbee devices, the reports of their Command Classes and Clusters respectively go through the corresponding handlers. When you issue a command from the API, the driver sends the Z-Wave or Zigbee message to change the status in the physical device but you cannot send commands to capabilities without commands like “temperatureMeasurement” since only the device reports should populate them.