Why did the Yu-Gi-Oh! anime change the dueling boxes/tables used in Duelist Kingdom to large platforms?
Sitting down in an enclosed box that displays holograms of a small size doesn't spruce up the intense battle scenes that the manga wants to convey to the audience. Also sketching huge monsters as holograms in manga comics is difficult keeping in mind that the dueling field needs to showcase both the monsters and the duelists. It would take up a large space on the page.

Also when the anime was being created, the emphasis was made to make duels more interactive than just showing monsters screaming. Like monsters could now be launched from canons, Gaia the Fierce Knight could now gallop and much more.