I have an S7. I did not see any playlists available for transfer to the Gear until I downloaded and installed Samsung Music. My guess is that you may need Samsung Music installed to get the Send Content to Gear working correctly for Music.
I had this issue with both my S4 and my Note 4 and Tab S Tablet. I have an ASUS router and found a solution to the 5GHz wireless dropout.
There are 2 settings that if available on your router you should change.
Network Key Rotation Interval = 0
Control Channel = Set this to an non-used...