And some of us may keep track of expenses for reasons other than budget. I know I have a lot of expense data that I look at from time to time out of curiosity. No way I need to change my behavior as a result of having the data. If I do plan a long trip I like to know I can position the cash to cover it in advance so when the bills come in they get paid without my having to do anything further.
Also when someone asks about expenses I can report what my expenses have been based on my own experience not a SWAG. Just one person's rationale for seeming to be OCD about expenditures.
To get back on topic, I run what I need to be comfortable and to keep DW comfortable (even more important).