I've seen this done before and it can be nice, it can be manipulative, and it can be distracting, not to even mention the valid point that those who are hard of hearing will have a hard time understanding the sermon. The musician doing the playing needs to be very good to be able to do this well and not just be a distraction. Many aren't this good and it turns into a disaster. Also, even if you have the right musician and the right speaker to make this work, there is still a time and place for it, and I don't think that time and place is at every Sunday sermon. But then, that's just my personal preference.