You can absolutely fill your keg from cans or bottles, it's not the main reason we designed the mini keg (we'd like to prevent as many cans and bottles being used in the first place as possible) and it's not the best method but there are good reasons why you might want to: Pour from a beer tap. Most people prefer a pub quality draft beer over a can or bottle, plus it looks cool!No chance of broken glass in the pool, on the beach, in the park etc. Stays cold all day without needing to cart around an esky and ice (when using an iKegger insulated keg)You can transfer straight to a keg while at the shops and get the money for the cans / bottles back straight away. No rubbish piling up at home.Don't need to bring alll the rubbish with you (great in limited space like a caravan).Don't need to bring the rubbish home with you (if you are going into a national park, camping, on a boat etc)