Do you need a satchel?
Short answer: Probably. The satchel protects the windblocker from scratching and abrasion for the few times per year you take it out of your car and want to store it or set it aside. If you're going to leave the windblocker in your call all of the time, then you don't need one. If you're going to take the windblocker out of the car, even occasionally such as when cleaning your car, then I'd get one. By the way, in case you suspect it, we're not pushing the satchel for the increased business. For us the satchels are a break-even deal. Our seamstress is the one who makes the money from them, not us!
What Type of Satchel: Cloth or Vinyl?
Short answer: Functionally equivalent, but the vinyl is nicer. Both satchels will do the same job and last the lifetime of the windblocker. The vinyl is a nicer material, and has a softer fleece liner, so it's a higher quality item. If you're tight on cash, get the cloth satchel; else, the vinyl is a nice upgrade for an extra $6.