A car insurance company asks the primary use of a motor vehicle as part of the application since, typically, how you use your vehicle is one of the main rating factors of your policy.
You would choose pleasure as the primary use of your vehicle if your driving doesn't include driving to and from work. It also cannot be selected when you use your vehicle to drive to and from school. Those driving situations that are defined in another vehicle use, would remove it from the pleasure-use designation.
The difference between a commuter car and one for pleasure is that basically the commuter car is one you use every day to drive to work and back or school and back while a pleasure car is only used occasionally for like during the weekend or on for fun every now and then but not driven on a regular basis
Reference: https://www.carinsurance.com/kb/commute-vs-pleasure-vehicles.aspx