At Costco 2 96 oz bottles are under $10 which makes it around $3.30 for each 64 oz. Some like the taste better and some like the 64 oz bottle taste.
2 x 96oz = $9 (usually) at Costco (Bingo had it too a week ago same price, might still have it). That comes out to $3 for 64oz.
Not everybody lives near Costco (or has membership) though. Also factor in time and hassle of shlepping cases of bottles.