This would be a minor tweak,
I like sharing my listening with my friends but dont always want their activity screaming at me while browsing for music on spotify.
It would make hiding the right sidebar with friend activity easier. You could add it as an option in the current drop down menu near your username (currently has private session, acount, settings, log out). Or you could add a new button alltogether making it easier to toggle the feed on/off.
Updated on 2017-09-13
You can also go to the top left menu => View and toggle off the right sidebar. ;)