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.
Maybe, but there could be other reasons.
In a former life I briefly worked at a game developer, and the PC port of a game we shipped did the same thing. The reason I got was that the assets were just barely too big for the game to ship on one CD-ROM and going to a second disc was going to cost too much. The solution was to encode all the sound assets into .ogg (because it was free and unencumbered) to put on the disc and then convert them all to .wav post-install because the in-house engine couldn't play .ogg files and there was no time to add support before publishing.
Given two files, a compressed file which must be uncompressed to play, and an uncompressed one which does not require extra processing - why would the game ever bother uncompressing te compressed file when the same data is already available uncompressed?
There's no true use case for that that I can see.
In this case it was stated that both the compressed and decompressed versions live side by side. So there is no install size saved.
"The game Titanfall on PC has the audio in it twice, compressed and decompressed."
'has it twice' could just be on the install media, and compressed/ uncompressed chosen as a trade off between install size and performance.
Anyway searching around the OP seems to be misrembering. Titanfall seems to be well-known for 35gb out of the 48gb install being uncompressed audio. I couldn't find a reference to it also having compressed audio also.