Just to say that this thread is still relevant. I use garageband to record acoustic instruments with a microphone. That is all. I discovered in the storage optimising settings of OSX that I could delete these electronic instrument libraries and whatever else and so I did. To save space. It's a PITA that each time I launch Garageband it tries to download them again. They're not necessary for my simple recording usage and 2GB costs money on a 500GB Macbook Pro M1. Like 2/500 of 3500 euros = 14 euros! Haha not that bad but I don't want to run out of space and have to get a new laptop!