It doesn’t, see my posts:
Widget input: It SMELLS - #4 by Roy_Wierer.Seda145
Widget input bubbling for InputComponent->BindAction?
UE5.1.1
Having an input component on UserWidgets is useless in the first place because all input is routed and processed through an entirely different system, which you use by overriding a widget’s OnKeyDown and other related methods. If you’d use BindInputAction on an input component you lose the routing, prioritization, handling logic + that it doesn’t execute in the playercontroller’s input mode UI.
Trust me I’ve been trying to unfck this for way longer than I should have.