But, I'm wondering what the advantage is to mastering to tape (I assume a bounced final mix) which I've heard people do to "add the effects of tape".
I can't see how this can be a good idea. I can only imagine mastering to tape would make the recording sound murkier. I prefer only to use tape once anyway. For backup, I usually record straight to tape and digitally at the same time (despite the inevitable stretch shifting with tape).