When entering a queue the intro message is played over the top of moh. This simply doesn't work when the moh is speech. You just get a mish mash of unintelligible voices. Furthermore, some people require ringback before a message. This could be spliced into the intro, but background moh ruins this. I can't think of any compelling reason to have moh in the background, but if it could be disabled, or the level could be adjusted, even via an advanced parameter, everyone could be happy.