It's not about size or file count or disk space consumed. The question is about why would you require the extra overhead of playing the compressed version which involves decompressing it on the fly in some way, versus just playing the already decompressed version.
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.
So, if a corporation can suck up entire books to teach their machines how to think using the information from those books, can we (all humans) join a single corporation that provides all books to its employees? Just need one copy of each and we'll make that copy digitally available for our employees so they can learn from and utilize the knowledge from the books. It's not copyright infringement, they're employees.