*puts on serious mask*
Since we all know any rechargeable batteries in commercial market eventually loses their capacity due to chemical reaction and would eventually flat out, technically u do have to replace it... eventually anyway, but hopefully before it loses significant amount of charge capacity the device's mechanical components wear will already be significant enough that the battery life span is of lesser concern.
since this is likely a scissor switch keyboard, such mechanical failure is very likely in heavy use as scissor switch are not exactly known to be that durable. But then again whoever is gonna be using such keyboard probably don't really need it for heavy use anyway so it's portability and convenience may well outweigh all other concern.
still... it kinda disturb me to see price tag over 60 bucks for non mechanical keyboard with doo dads attached, though i'd admit the portability can be useful in some cases.