Why powerbanks cut-off load when charging?

And, Why mobile phones and laptops do not cut-off while charging?

Is there a reason why they design pb's like that?

What cut-off? They all work the exact same way. When charged reduce the voltage to prevent over charging, but still supply power for the load.

Oooh, nearly all my powerbanks cut-off load when i plugin the charge usb socket. I use some usb gadgets like ledlbulbs and i have to plugout the charge before i can load.

In fact my question is. Will it effect the li-ion battery when you load while charging? I usually discharge only 30%

With this module i can also load and if the incoming amps is higer than the load i think it will chage the li-ion also, with discharge protection