Wi-Fi may be the most popular method of connecting devices in the home and, increasingly, on the move but in an office or enterprise setting cabled Ethernet is generally all-pervasive. As that's the target environment for Windows 10 Mobiles running in Continuum mode it's good to know that USB Ethernet adapters are supported by the Lumia 950 and the Microsoft Display Dock.
For HP Elite x3 users the Desktop Dock has an Ethernet port built-in, so its not in question, whilst the third phone currently supporting Continuum, the Acer Jade Primo should also support USB Ethernet adapters based on the results with the Lumia 950.
Unfortunately what's missing from Windows 10 Mobile at the moment is any kind of indication that Ethernet is in use, rather than a Wi-Fi or 4G connection. To be absolutely sure I had to put my Lumia 950 into flight mode and see whether a connection was still present. That doesn't necessarily guarantee that a Windows Mobile will prioritise wired over wireless connections, but it does seem a logical step.
As more options appear for the virtualisation of desktop apps for use in Continuum the strategy becomes more viable at an enterprise level. However I can't help but think that any organisation that removes its laptops in favour of Continuum toting phones will have to have a very specific set of use cases in mind, none of which involve any kind of mainstream computing on the move.