The benefit of using plastic bottles is that you can ditch them and/or replace them every day. I wouldn't carry more than 3L (2 of the 1.5 water bottles common in Africa) in throw away bottles, if I needed more i'd go for something more permanent. This question, I believe, was about Morrocco and doing some touring. As big as the continent is, here in West Africa we can usually find fuel every 50 miles or so pretty easily, with 100 miles being moderately common, and 200 miles very rare. Keep in mind there are 100cc motos everywhere who only have 1.5 gallon tanks. On my West African touring, in Benin, Togo, Ghana, Burkina Faso, and Mali it was sometimes better to have a worn out t-shirt to filter fuel with than it was to carry spares. I can almost always get fuel on the side of the roads in 1L glass bottles (set up in little stands) but often preferred passing it through a shirt and praying it wasn't too cut with water or kerosene. On my bike, a XR650, I had a 4.7 gallon tank that easily got me 200 miles before reserve and carried 1.5-3L of fuel on top of my pack under a bungee top facing up at an angle. I kept it there so that if I fell I wouldn't crush it. I never had one leak. I never needed it but it kept me from worrying and kept me from carrying big jerry cans (1 gal of fuel plus weight on those square tanks and racks has to be 12-15bs) and when it's clear major cities are close enough not to need them I chuck them and have new ones next time I buy some water. You can insult folks, call them dumb, etc. but I wager most doing stuff like this are the ones who've actually ridden their bikes off the beaten path and spend their money on plane tickets and tires instead of utopian farkles you rarely need. This is coming from a guy who's logged 10k miles in Africa and a cross country and back US trip without all the extras. So buy em' if you want them but lay off the insults to those of us who prefer a little more ADV in our rides.