I was kind of thinking of it from a couple of different angles:
1. Keeping code concise, i.e. avoiding having to declare another handle, track it and send destroy to it. And in a more complicated situation, where many and potentially a variable number of dynamic objects are created requiring stuffing them in an array anyway, it might actually be cleaner to leave the object tracking/destruction up to some generic code.
2. Reducing the cognitive load on the programmer/maintainer.

If I ever were to use this it might be in the form of a class like this:

Class cDynamicObjectScope is a cObject
    Procedure Construct_object
        Forward Send Construct_Object
        Property Handle[] phoObjects
    Procedure DoAddObjectToScope Handle hoObject
        Handle[] ahoObjects
        Get phoObjects to ahoObjects
        Move hoObject to ahoObjects[SizeOfArray(ahoObjects)]
        Set phoObjects to ahoObjects
    Function AddObjectToScope Handle hoObject returns handle
        Send DoAddObjectToScope hoObject
        Function_Return hoHandle

    Function Create Integer iClassId Returns Handle
        Handle hoObject
        Forward Get Create iClassId to hoObject 
        Send DoAddObjectToScope hoObject    
        Function_Return hoObject
    Procedure end_construct_object
        Handle[] ahoObjects
        Integer i iCnt
        Forward Send End_Construct_Object
        Get phoObjects to ahoObjects
        Move (SizeOfArray(ahoObjects)-1) to iCnt
        For i from 0 to iCnt
            Send Destroy to ahoObjects[i]
        Send Destroy 

// usage:

Procedure DoSomething
    // do some stuff
    object oObjects is a cDynamicObjectScope
        // code in here creates dynamic objects with "get Create (RefClass(class))"
    // dynamic objects are automatically destroyed at this point
    // as is the oObjects object
    // do more stuff
This doesn't handle cases like cJsonObject that internally creates a new DataFlex object; you would still have to get the handle to a local variable and call DoAddObjectToScope to handle it with this class, or wrap AddObjectToScope around the Member(hoJson,"foo")