WHY is spotify 8.57 gigabytes?

[HuniSenpai]

From what I've gathered from other forum posts, it's from Spotify's stored data. Why is Spotify storing that much data though? Is it storing songs?  I thought Spotify only saved songs for offline usage for premium users (I'm on the free version). 

If I delete everthing in my data folder (that folder is 7.8 GB!!) will I experience any problems? I imagine Spotify didn't use up that much space just for nothin', but, apparently, other threads say that you can just delete it. If you can just delete it, then evidently it's not that important, and, therefore, what's the point of using up that much storage?

I have slow internet, so I suppose I do like the idea of cacheing songs, but maybe not if it takes up that much space on my SSD.