Yes, because "just magic" is context, the physics of the bike isn't contradictory to the lore, it is contradictory to game design, you are mixing up what it is that doesn't make sense. I can give myself the suspension of disbelief of a tiger flying so long as I am given context and suitable animations, but if I am given no context and the tiger just no-clips its way through the world, that is extremely poor implementation. The problem with the bike is that it presents contextual challenges within the movement design, and that has nothing to do with lore or context within the world.
You say this is a fantasy game, but it still needs to stick to its own rules regarding physics (which in this case is close to real world)
