It would be interesting to throw this on a kill-a-watt unit to see exactly how much it is using.
I would not expect LED's to take hardly any energy. What I would expect to take power is whatever embedded microprocessor is in there for signaling to the car, etc... I do wonder if it has firmware and if so, is it updatable? And how?
The other thing I would expect to take power is the contactor that turns the power on and off. When engaged, that is a electromagnet.
Are you feeling it warm when it is plugged into a car but not charging? Or just when plugged into the wall but not into a car? (I could see if it is keeping the contactor engaged all the time to supply power to the car it could be using more power) Though I think the EVSEs may turn off power to the car when charging is done and turn it back on as needed?
FWIW though, compared to the 11.5kw my car uses when charging I guess vampire loss is not a huge concern to me. ;-) Yeah, it is constant loss all the time, but perhaps in the noise. I also don't leave my UMC plugged in ever since I have a Wall Connector (you now make me wonder how much it draws).