I’ve posted how I came to iNaturalist before so I won’t repeat myself again.
What I get out of it now is almost the same feeling I used to get as a child when my mother would order an encyclopedia set and once a month a box would arrive with the next letter or portion of a letter, which is to say a sense of wonder and learning and an awareness that the world is so much larger than I could ever imagine. Just like those wonderful books I remember, iNaturalist makes me quietly introspective and makes my brain tingly with information connections and also makes me a little awkward in that I want to share things and photos with people that are possibly only interesting to me.