Scott wrote:

Sorry, a basic question. Do these devices detract from energy
efficiency?

Yes they eat a little power

If leaving stuff on stand-by is frowned upon, is a UPS
not even worse?

The energy police haven't busted down my door yet, I choose to pay a
little extra to keep stuff running (last time I checked the event log it
had supplied power 11 times in 14 months, some for seconds, others for
tens of minutes).