These two are stateHandlers are equal:

const [state, setState] = useState()

  stateHandler = {(newValue) => setState(newValue)} // first way to pass it
  stateHandler = {setState} // second way to pass it

Same with onClick - you can pass it both ways

const handleClick = (values) => {
// do sth
}

onClick = {handleClick} // same
onClick = {(values) => handleClick(values)} // same

Edit:

Based on the comments I will modify my question a bit:

(values) => handleClick(values) is also a function that calls setState, but why are you not asking how that function receives its argument?

This is what I am asking here probably, yes. Thank you for pointing me