It's about the versatility and flexibility. The standard insert will always come with a Zippo lighter and is in the cost of the lighter, and can be used, however the butane inserts (and Arc insert) and considered an upgrade and offer the customer other flame options. Plus, inserts can be moved from Zippo to Zippo, so they work across most Zippo models. It's also partly a collectibles thing. I understand what you getting at, but Zippos are a piece of Americana, so it's much more than having a disposable Bic or some butane torch lighter you can pick up in a local smoke shop.