I really like that key chain! I was looking at it a few days ago. It reminded me of dice. If it was a set of dice I would have bought it for mey son - he collects dice. I think it would look nice on a piece of Graphite or black leather. Go for it!
Yes. If you're looking for something masculine then this is it. Of course, for a bag charm to be carried by a male, doesn't necessarily mean it needs to be masculine. It's really just your preference.