I’ve actually considered it, mainly because it’d be useful for me to document what I do and how while keeping my hands free.
My job involves a lot of hardware troubleshooting, and when people ask me a year later when and how some specific issue was resolved, it’d be a whole lot easier to check the tape.
Yes, taking notes is possible, but when you’re troubleshooting an industrial system, and downtime costs 40.000$ per hour, updating your diary isn’t exactly a priority.
I don’t really have much of a privacy aspect to worry about - the only time it’d be beneficial for anyone would be while doing field work, and at that time I usually have 10-20 people waiting on me anyway.
I haven’t found a durable camera that I can wear discreetly, though.