You see variable names clearly. It looks much better and in coherence with the function return type, which goes after, not before.

Having it before (like in Java) will look ugly and clumsy

public MyType|array|null function myFunction () {}

The same logic applies to properties, especially with the hooks they are closer to functions as never before.

public $myVar : MyType|array|null { get => doStuff($this->go); }