Sync local files through USB

[plattagran]

This seems to be impossible, pretty amusing considering the sign "never be without your music" is screened when pressing the devices-tab. If you do not have access to WI-FI this statement is not true, my only option is to sync local files through USB which is not possible, in other words I'm without my music in this position... As the legend says; never say never 😉 Pls fix this Spotify.
Is there any work-around for this? 

Kind regards
Jonas