it becomes cumbersome and boring for the co-passengers in a long trip without any music.
Normally during daily commute in city traffic, I am the lone person, So I can switch it ON/OFF depending on mood. But I don't keep it OFF all the time, I have few CDs of my favorite songs and prefer those over the loud music of FM. Also, now a days there are less songs and more advertisements on all FM channels.
But when it comes to long journey with family, it's required to be ON.