I think we need to look back at the OP.
If you were limited to one EDC item.
I am not likely to carry a locator beacon with me to the store, even GPS would be an unlikely pocket item.

Lighters and small pocket knives are in the pocket trash class.
So is a bit of string or wire, a few bandaids, a button compass, and a host of similar items.
From there it moves up to a personal FAK and the BOB levels.

The point that at least one person made about when and where you are makes some difference, but as EDC I think in general terms, and then modify what I do actually have to the situation I am expecting.
If I am boating on a lake I want a life jacket, if I am driving in the desert I want full water jugs, but neither of those make it as EDC