Having been around that block a few times, I'll aver one can never have too many good car towels.
I always carry a couple in the car and a couple in the trunk. When driving leisurely, I keep a small towel on the arm rest so it doesn't build up oil from my skin, which will happen over time without it. Towels are handy for those occasional untidy moments. With your extra towels, consider carrying a small spritzer of detailing spray to address the occasional spot of bird crap or other hazard.