You need to distinguish between physics and mathematics. The explainer is about math. Here, 2D absolutely has volume (i.e. area). Also, higher dimensionality sp

You need to distinguish between physics and mathematics. The explainer is about math. Here, 2D absolutely has volume (i.e. area). Also, higher dimensionality spaces are the same: each dimension uses the same units, therefore r is always the same. Thinking in "time" dimension doesn't help here imho.