Why use functions like CGRectMake?

I'm curious why functions like CGRectMake and CGPointMake exist and are widely used. when, instead, you can do:

(CGRect){{x, y}, {width, height}}

surely this is more efficient (though I'm guessing not by much) as there is no function call?

Also you can set the origin and size like:

 (CGRect){origin, size}

and as a mixture:

 (CGRect){origin, {width, height}}

What is the reason for not using this, and preferring the Make functions?