I think the peace-of-mind element is worth something. The times we've needed a tow, we're already behind schedule because of whatever prompted the tow. To start looking around for some towing company -- especially out of town and especially before the era of smartphones on cheap data plans -- is just one more hassle.
Maybe in the age of gigabytes of cellular data and yelp and the like, that part of auto-club service is as duplicative as trip-mapping. But having just one number to call still has its fans.