i don't think anyone is really STORING e85 in 5 gallon jugs. the people storing it are mostly using 55 gallon drums or things of similar size. most people use the 5 gallon jugs as sort of a "range extender" for their gas tank.
for example: i use my three 5 gallon jugs when i go on road trips that don't have e85 stations readily available along the way. this allows me to have a highway range of about 600 miles instead of only 300 miles. i could easily just switch maps, but where's the adventure in that...plus, nobody wants to lose 100whp...