You have to remember that there are actually a lot of companies out there that are doing contracting work and working on the hour for various clients. For those clients you need to show what you're billing them for.
On top of that, it could be for any kind of work - not just programming - design, engineering work, contractor work (builders etc), electricians, you name it...
On top of that, it could be for any kind of work - not just programming - design, engineering work, contractor work (builders etc), electricians, you name it...