Plant health comes first... If you put it in a glass ball, indoors, I am betting you will never get enough airflow & direct-sunlight on the plant to avoid fungus & overcooking trouble.
IF I were to consider such a contraption (Which I agree, from an pure view point of view could look cool, but that is leaving out any other feelings I have), I would always want such a thing to be outside in a semi-shaded spot, say, hanging in a full-sized A Palmatum in the garden.
As for those who outright call these things stupid, keep an open mind. not all things that are non-traditional are stupid. Some are exceptionally cool. Let people experiment, and see what works, and what doesn't...
Tickle, Noelanders 2014
Nick Lenz, art of bonsai
Takanori Aiba, bonsai treehouses