most of the use cases i can think of would have the phone plugged in somewhere permanently, digital photo frame, home assistant controller etc, so whether the battery is worn out wouldnt matter so much
>whether the battery is worn out wouldnt matter so much
Old phone batteries bloat up and become fire hazards. Ideally, phones could run permanentaly plugged in with the battery removed, but from my experience, they won't even power on without a battery present.
were that true the charge time would be longer than the run time (not strictly true, if the load is bursty what you say could conceivably be true)
its somewhat difficult and fussy to do power management in the way you would expect - that the input power is used to power the computer, and whatever is 'left over' is used to charge the battery.
this is just skimping on engineering bandwidth and a few extra components
