Split diopter auxiliary lenses

I just bought a +2 split diopter lens. The idea behind these is to be able to get sharp focus on both a foreground object and a background object. There is an in-between region that will not be in sharp focus, but depending you the composition of the shot the intermediate region might not be very important. In fact, in some favorable cases it might even be just empty space.

Anyway, has anyone here used those devices, and if so what are your thoughts?

They had been popular, there also where versions with a central hole.
I got several of these. As kind of last resort concerning focusing.

That transitiuon zone one can consider advantageous or disadventageous and try to place it respectively.