Um, you’ve got 20 gallons in the truck in the garage and maybe another vehicle and you don’t want to store 5 gallons in a can. All the gas tank is is a glorified gas can. Plus you need to use a fuel conditioner and non-oxy fuel for that or when you need the generator, you’ll be pulling the carb apart by candle light trying to get all the gum out. I’ve got a 5 gallon can, a one gallone can, and a one gallon can of mixed in my garage and no problem for 30 years. Plus I’ve got 5 gallons of kerosene and about 60 gallons in the vehicles.