As for "cheaper than the real thing", I don't think it has to be.
It has one major advantage... It's new. You shouldn't have to worry about leaking batteries or CAPs or whatever has been spilled on it in it's lifetime.
(Yes, you get to spill all of your OWN soda/coffee/tea variations on it!!)
So, you'd kind of be comparing it more to NOS type of priced Amigas.
Then you throw in a processor accelerator with some memory and a Flicker Fixer, and you're actually getting to the possibility that the Natami might be less expensive than a NOS Amiga 1200 with Mem/Accelerator/FF.