When Metal Gear Solid 4 released on Ps3, they used uncompressed audio. I think part of it was just to show off how much storage Blu Ray had.
The game Titanfall on PC has the audio in it twice, compressed and decompressed. The decompressed was for machines with dual core or less so that there was enough overhead to keep the game running.
Why would it play the compressed version if it had the decompressed audio right there though?