Observation for me can be a discipline to concentrate on the world around me and write from that.
Observation is useful in writing, though.
I may relate my observations to my writing foundations and build a story out of it, that’s part me, part other.
At the extreme is complete detachment on behalf of the writer and it is interesting where this may lead. Does one see it from someone else’s perspective completely?
Observing someone or something else or observing some other “world” invariably requires research to understand that someone or something other.