I don't think that people necessarily expect complete privacy in public places (although this was one thing that caused anger about the original Google Glass). The people using this version for work are leaving them at work when they head home. These are work only devices. But there is a risk associated with having a device that your employer requires you to wear, that can also record video and audio. It has the potential to capture the everyday mundane conversations you have with colleagues, which might contain something that could cause you a lot of problems later if taken out of context.
The vast majority of employers wouldn't cross that line and start recording their employees, but to compare to smartphone use - Would you pull out your smartphone and hit record every time you talked to someone at work, just in case your employer wanted to listen to those recordings later?
If your company trusts you to do your work, and you trust your company not to record you, then the privacy problem is not that important in your case.