It does require a certain level of... Commitment. I guess if you're used to having a notepad or something around to write down details - this would be the digital equivalent.
Bob, you're absolutely right - there are a lot of ways to edit EXIF info. This app is kind of meant to be used on both ends of the process... Capture details while out snapping, and flesh out or correct once scanned.
I've always kept a small pad and pen handy in the camera bag - but I can't really say I use it to write down exposures, locations, etc. (though that was the idea). I guess with film I just don't really care so much... Part of why it's so liberating.