I agree that keeping a QMS secret is nearly impossible. After all, customers may get to see it too and who knows what will happen then?
However, it's certainly worthwhile to have some kind of information control. I am an internal auditor and some of my employer's sensitive information is password protected, not available for me to look at except during an audit. And that's okay! In fact, I praise them for it because it shows they have been thinking about control of documentation, safety both from inadvertent erasure and intellectual rights.
If you have a skilled IT person, (s)he should be able to set up password-secure drives or folders for your more sensitive data. I doubt competitors would care much about the routine stuff.
Once finished with password-protecting sensitive information, your work is not finished. Besides the excellent feedback about keeping people happy, I can vouch that some of the most notorious IT crackers (the IT community doesn't call everyone a hacker, as there can be good hackers too) accomplished their infiltration by "cracking" passwords of careless employees.