Mongolian/Dutch girl here, raised in Buddhism, right down to attending Hongwanji Mission School for elementary and middle school education. I have to say that I have absolutely no problems with people using our beads or symbols so long as it isn't for fashion or trend reasons. If it brings someone peace, joy, or happiness to gaze at the prayer beads in a way a poster would not, I more than encourage it, and I was raised to encourage people to find their own personal paths to a peaceful life.