I wonder what a genuine conversation with a JW about this would be like. Firstly, I doubt that it would come up with a householder when they're out in field service. The "spiritual paradise" is, as I understand it, internal jargon used for mutual encouragement. I'd have to raise it as a subject.
Then, both those words would need defining. First, what do they mean by "spiritual"? The term itself is somewhat nebulous. Is there some sense of euphoria, of being closer to God, when they're in the Kingdom Hall? Or does "spiritual" mean "figurative"? In which case the "real" paradise would have to be defined. What is it like*? And how is the "spiritual paradise" like "actual paradise"?
I actually kind of miss the days when you could have a conversation like this with a JW at the door.
ETA: I should have read through the thread before posting the above. It seems that they have a definition in the literature, even going so far as to say that it is part of their "theocratic vocabulary"**. It doesn't preclude the above hypothetical conversation, however. I genuinely don't know the minutiae of their doctrine, and I doubt someone at the door will have that stuff memorised.
*For all those pictures of paradise published in their literature, what it entails is not very well defined.
** Remember the argument that the word Trinity doesn't appear in the Bible, so the doctrine must be false? I don't remember seeing the terms "spiritual paradise" nor "theocratic vocabulary" either. 🙄