Here myObj is just an properties collection. i.e. Some description object. that's all. This is not an TestObject or Runtime Object of UFT's kind.
Set myObj = Description.Create
myObj("html") = "B"
myObj("html tag") = "Pizza"
B.P.Button(myObj).click 'OK so far
Once you pass this properties collection to UFT's class type like,
Now B.P.Button(myObj) is a RunTime Object of UFT's kind and you can use GetROProperty or .Object here.
Also if you want to see the properties collection, you can do as usual handling DO like;
But this will not change unless you modify it.