Does the compressed packaging of a game lower the quality?

Hi does the quality get lower in game when packaging it using “create compressed cooked packages” ?
If i want best possible quality, should i keep it uncompressed when packaging my game ?

Nope, it just an attempt to get the PAK size down, as I understand. The problem with compressing though, is that the end user has to decompress. I think, every time they run it.

Yeah it has not to do with quality, but it may impact performance in some way(loading times?).
Typically I would not compress untill the game becomes big (like many GB).