Comment by oskarkk
I haven't used them, but IIRC they maintain a constant voltage until they're discharged, when it instantly drops to 0. That may be a problem, because if your device has any battery indicator, it will show the battery as full until the end. Nothing will tell you that you need to replace the battery before the device powers off. That's why I decided not to buy them. My mouse knows when my alkaline AA battery is low and gives me a warning.
You can get them with different voltage drop-off curves
E.g., this battery is 1.5V for ~70% of the capacity, before it gradually reduce to 1.0 V
https://www.xtar.cc/product/xtar-1-5v-aa-clr-3300-lithium-ba...
edit: And one with USB-C and linearly decreasing voltage curve https://www.xtar.cc/product/xtar-aa-lithium-lr-2000mah-usb-c...