There's also the fact that your documentation will probably survive any unfortunate encounter any one of us might have with a bus. Nevermind the prospect of untimely demises, etc..., it is encumbent on every role to leave behind enough information for the organization to pick up what we've done. A backup of existing scripts (even stored in a historical form) isn't documentation, since it only captures WHAT was done.

The value of documentation increases when it provides insight in the WHY, the consequences of the HOW, and the reasons as of the WHEN you did the WHAT. That's always been why "self-documenting code" isn't.