While I can see an argument for your co-workers learning some signs because of you, I'm not sure if learning new languages on the basis of what might happen in life is a strong argument. Using that logic, a person might suggest that a deaf signing person should learn to hear and speak, in case they break their hands, become paraplegic or go blind. You can see the difficulties here. And where does it stop? Should I learn French because one day, you never know, I might go and live in France? The possibilities of preparing for everything that might happen in life could be endless.
For a hearing person who becomes deaf later in life, it's much easier to have a relatively safe CI operation (if hearing aids are not helpful) and use what they already know than learn a new language completely from scratch, change all their friends to signing ones (because lets face it, their hearing family and friends will likely either not learn sign or not learn it to a very high level). And well, if they ever go blind, they will still have their CI.
