I use the bookmark feature a lot when trying to map because i have trouble finding the rhythm so i bookmark it out then map to it, but sometimes i need to bookmark other important sections like parts i wasn't to sure about that i'd like to redo later, etc. I think it could be useful if you were able to color code bookmarks for different things or just to have a different color based on what you want. i don't see any reason why this shouldn't be added and i assume it'd be easy to add/change.