7:36 - Actually having AA (or AAA) batteries is more eco-friendly than bespoke, custom made battery which you can use with one specific device and after 2-3 years when you need to replace it you start to swear because the manufacturer didn't plan for it. Eventually you find out you can't get a genuine replacement and buy a cheap knock of which lasts for 3 months and in frustration you bin the whole device and go and buy a new one. No one, in their right state of mind, uses a non-rechargable AA/AAA batteries anymore.