If you are taking a larger or heavier older sewing machine to classes, and have a ways to go from car to classroom, or regularly take it on the train/aircraft, then yes. Personally, for that I'd go for the wheeled sort. People like Janome and Brnina have own brand ones that fit their machines. Expensive, but worth it for a big expensive machine.
Usually when I'm sewing away from home I don't need to move the machine far from car to resting place, and I have the GMNT and his dad handy for carrying, so I just use the machine's standard case. I also usually use a smaller machine when away from home, such as the Elna Lotus machines or the Frister & Rossman Cu 4's. I do have a generic carrying case for my sergers, but only the one as I don't usually need to take two away with me.