^Aren't you forgetting that the miniature has already been on display in the museum for over 38 years?
When it was donated to the Smithsonian in the first place, they chose to put it in the NASM rather than some other museum. They displayed it prominently in various NASM galleries from 1974 to 1993, and aside from loaning it to the Hayden Planetarium for a year, they've never displayed it in any other museum except the NASM. I just don't understand the argument that it doesn't belong in that museum when that's the museum where it's been for most of its lifespan. If it had never been there and someone were proposing moving it there for the first time, then your arguments might make some kind of sense; but that's where it's actually been
for nearly four decades, so why is it suddenly wrong to keep it there?