I understand the logic of not signalling if no-one benefits - but it's just not possible to guarantee that no-one benefits - and there's no harm in a signal no-one sees.
There is absolutely no harm in giving a signal that no one sees, at all.
The point is, I'm talking about an advanced driving technique which enhances observations and overall awareness of everything that is going on around you, at all times.
You may decide at particular moment in time that a signal isn't needed but, if circumstances change and a signal can be of benefit, then one is given. But, this takes constant observation and understanding of the road scene all around you. Whereas, automatically signalling negates the need for constant observation.
There are, on the other hand, times when I will give a signal when nobody else is in sight but, I judge that the situation could change very quickly. For instance, one of my routes involves turning left onto a fast A road on a right-hand bend and I have to turn right into a junction 50 yards along the road. As soon as I turn left I put my right indicator on so that if anything should come around the bend behind me they will see that I intend to turn right.
It's not a big thing, the vast majority of drivers signal automatically for all occasions, without a second thought.
My main pet hate though, is drivers who negotiate roundabouts with a right indicator on which isn't cancelled when they exit. This has completely the opposite effect of giving a signal which is of benefit to other road users.