There's a bit more to the differences than that, Nanase.

I wasn't sure if I wanted to animate the chair in any way. I can see an argument for the chair being totally stationary, and Nanase seemingly teleporting around during in-character moments. In some ways, it makes more sense metaphorically for the chair to remain totally stationary.

The counter-argument, however, is being able to show strange stuff with the chair, and starting debates over whether it's floating or hopping.

Ooh, and maybe debates over whether Nanase can float around on a chair out of the game? She CAN fly, after all.