Why add the () outside the return statement when you omit the return {} syntax?

The Counter class contains the two increment/decrement methods. In the video, Guil shows two ways to write the methods.

--First with a return statement:

incrementScore = () => { this.setState( prevState => { return { score: prevState.score - 1 } }) }

--> returns object with updated score

--Then simplifies by omitting return statement:

incrementScore = () => { this.setState( prevState => ({ score: prevState.score + 1 })); }

--> return statement omitted, which should eliminate need for return {}, but why then add extra parenthesis around the object:

param => ( {/* object to return */} )

Omitting the return statement is cleaner, but why add the additional parenthesis on the outside? it breaks the syntax of omitting the return statement in an ordinary arrow function

Return statement:

this.setState( stateReferenceParam => { return { /* Object to return */ } } )

Should simply remove keyword and brackets "return {}":

this.setState( stateReferenceParam => { / * Object to update state */} )

but also adds an additional () around the object:

this.setState( stateReferenceParam => ( { / * Object to update state */} ) )