I know these are currently out of fashion but I'm still thankful they exist.
Let's remind ourselves of devices that use(d) these standardized batteries:
- Toys
- Digital cameras
- Torches
- Gadgets like fans
- Wireless keyboards
- TV remotes
Thanks to having a standardized system of batteries,
- You can use the same battery across several devices. This is a no brainer but it's very practical.
- Batteries can charge quicker thanks to being put in a dedicated charger and not being limited by USB cables. (But yes I concede that USB has been updated for faster charging over the years)
- Devices don't have down time when their battery is charging. To charge, the battery is removed from the device and can immediately be replaced with a fresh one.
- You'll never have to trash a device due to an expired battery. Just buy a replacement. And building on this...
- Any improvements in future battery technology can be retro-fitted into your existing devices. And there is a high incentive for future improvement, because...
- An accessible (due to easy replacement) and large (due to many devices) battery market is very attractive to competition.
If you look at the pros I listed, they all happen to be things that would be very useful for electric cars. So I think it would aid the adoption of electric cars if their batteries were standardized too.
Tipp for people wanting to get into rechargeable AA and AAAs: get IKEA Ladda batteries and their charger. They are cheap and japanese made. Some people argue that they are just relabeled Panasonic eneloops!
Edit: Oh also if you used rechargeable batteries in the past and you remember them sucking that's probably true. But the battery chemistry is better now and it's possible that your batteries degraded quickly because of "dumb" chargers. Modern chargers like the gray 4 battery Ikea charger detect how and for how long to charge and thus will not ruin the batteries.
LADDA are my go-to as well. I recommended going with the wall charges and not the USB-A charger, since the latter juices them up very slowly (compared to the wall outlet or the storage+charge box).