When I hire a professional, my expectations are that that person will prove to be the professional that I hired. I did not intend to hire a student or intern whom, if they spent considerable time at the office studying for a certification that that would be a good thing. I hire the professional to attend to the priorities that I hired you for. While it’s great that you’re interested in learning, your priority should be those items that must get done each day – it’s why I hired you in the first place. Because if you told me that you’re going to make your priority building up your list of certifications, I would have just hired someone else.
All of my studying for different certifications was completed off the job, in my own time. I chose to take those certifications and know that my job description doesn't include studying. If said person has that much time at work it makes me wonder if they're doing anything productive. Believe me, CISSP study isn't something you want to traditionally spend an additional 20 hours of study a week on top of your work. But if you intend to be a professional, do your job during work time and progress your certifications on your own time unless your boss specifically states that you can set aside time for study.