Everybody is different, of course. I'm only tracking income out of curiosity. At this point, it doesn't really matter to me.
As for Word, I like it for small pieces like short stories, articles, or something like a resume or report. On the other hand, Word is not really that good for big documents or collections where you want to be able to rearrange the pieces. That's where I find Scrivener so useful. I can get the total word count for a collection of stories or essays, and it also has a feature where you can set target word counts. I'll probably be writing more about it in the future. Maybe it will change your mind--or not. When push comes to shove, we all have our favorites.