Rather than negate your usefulness, finding automation scripts and creating bulleted task documentation will make you more valuable than ever before, says Limoncelli. This is not like the auto industry, where robots put assembly lines of workers out of work. If sysadmins are not willing to learn some programming and overlap somewhat with the developers, then their job will be the maintainers of the automation and processes. Think of the robot maintenance engineers who were hired when the auto industry started using robots.
Here's a great developer analogy that Limoncelli added:
The C programming language let one programmer could be as productive as 100 assembly-language programmers. Did this mean that 99% of all programmers were fired? No, it meant that more programmers were hired than ever before: the profession was opened to more people and the pent up demand for software was release
So rather than hoarding the knowledge and keeping things manual, start doing the opposite if you're not doing it already. Check out Limoncelli's post on writing a bullet list and then read the post "Automate? Will I lose my Job?", which I just commented on.