Most weird stuff I grow is for one of two reasons (some a combination of both): 1) As a challenge or to experiment or 2) for Bonsai.
I obviously know that in Zone 5 B I can't grow a 50 ft Zone 9 plant that must be brought in.
But I can sure try to keep them at < 2 or 3 feet max. as a bonsai.
E. G. a 30 inch Cassia bicapsularis just finishing blooming in my basement.
Things I am doing this (Bonsai) with - 6 types of Bauhinia, 3 types of Commiphora, Ylang Ylang vine, 2 types of Boswellia, 2 types of Bursera, lemon, clementine, fig, pomegranate, pineapple and ~ a dozen more.
Latest? Coconut - just started today