I've never tried this with a banana plant, so I don't actually know this.

Every plant I've ever positioned "horizontally" has figured out which way is up, and new growth makes the turn upward. Still, I've never tried it with a banana, or with any other similar "pseudo stalked" plants like ginger or turmeric. You might get a "zig" in the stalk for the winter, and a "zag" next spring/summer when you put it back outside. Or it might just be very unhappy laying on it's side. If I were going to try that, I'd place them leaned over, but as close to "vertical" as my space allows rather than just laying it flat on the side.
Many folks that bring taller banana plants in for the winter and "lay them down" just bag the root ball and lay them in the basement/crawl space where it's dark, dry and cool (but not freezing cold) and let them spend the winter in a forced dormant state. That works for sure.

I bring mine in and keep them in a "tropical room," but mine aren't over 10 feet tall. I have "superdwarf" varieties, and they stay fairly short, about 4 to maybe 6 feet tops.