The nearest RedBox is only a 5-10 minute drive away. But renting that way still usually involves making a special trip to either pickup or drop off. Not really worth it to save $3 most of the time. I use RedBox but it's a very occasional thing--especially as I still have a minimal Netflix DVD by mail subscription.
Maybe you don't buy groceries, but I do. I need to eat, so I buy food from a grocery store. Conveniently enough, my local RedBox is located at my local grocery store. There's always something I can buy there to restock my refrigerator or panty. And if I wanted to watch RedBox movies, it'd be very convenient because I could pick it up there, along with some food.
If driving to your local grocery store is such a pain, you might want to re-evaluate your choice of city to live in. I've lived in a bunch of different places around the US and never seen a place where just getting to the local grocery store was that much time or trouble. (Work, sure, because the commute can be long and rush-hour traffic congested, but not the grocery store.)