For no reason?
Idiots who lap it up due to wanting all their speakers filled is a reaosn
Yep, it’s essentially 3D upconversion for audio. You’ve got a fancy new 3D TV and 21 channels of audio, and then you watch My Dinner with Andre and say “Hold up, what’s with this 2D video and mono audio crap!” So they hire a fly-by-night outfit do a 3D conversion, upmix the mono (and let me just tell you this actually happens and it’s exactly as bad as it sounds), and BOOM, they’ve got a disc they think is actually more appealing than the film was when it was actually in theatres.
That said, there’s a LITTLE bit of reason for messing with the audio IMO, and only just so much. Just as with video, when going back to the negatives means you lose the color timing and have to re-time everything to (hopefully) match, when going back to audio stems, you have to re-mix them as well. And theatre surround formats (e.g. 4.2) don’t quite match common home video surround formats, so a little remixing there may be warranted as well. If it’s done carefully, and with fidelity to the original in mind.