One of my deco units has an Ethernet switch with several devices connected to it, but is acting as a mesh network with the main unit in another room. 
 

Despite not receiving internet access from an Ethernet cable itself, this unit shows that it is connected via Ethernet and all the devices on it as well, including completely wireless devices, like my phone. 
 

additionally, devices that are much nearer to this unit aren't connecting when it feels like they should.