Ok, I don't use collision events, and I use 'other' and 'with' together often, but otherwise I don't need it.
The one case where I thought it might be useful is when you have instances of the same object pancaked together... And you're wanting to scrutinize the "others" and not calling instance.
is the solution I normally use for this, but it's just more tedious.
I had hoped 'other', when used in replacement of an object_index in functions like 'position_meeting', might do what I wanted, that is all.