I've carried moleskin (and molefoam) while backpacking, but I haven't found it that useful. I only really get blisters between toes, and usually only in one spot. If I have to walk a long distance, especially on a paved surface, I try to put some sort of lubricant between my toes that blister. A shot of lotion usually does it, but in a pinch I've used sunscreen or even a piece of chapstick. Or if I'm really desperate, I'll stuff some toilet paper or a fold of my sock between those two toes.

If I had a hotspot from a shoe rubbing against my foot, I'd cover it with a square of slick plastic from a ziploc or trash bag. It'll eliminate friction better than anything else I carry. In a pinch, I'd just wear a shopping bag between my foot and sock. I've done that when my boots have been soaked.

Anyone walking in an environment where they'd get blisters really needs to stop early and check for hotspots and treat them before they become blisters.