This visualization appears to be for batch gradient descent only, not stochastic or mini-batch. That said, your critique would be true of similar visualization

This visualization appears to be for batch gradient descent only, not stochastic or mini-batch. That said, your critique would be true of similar visualizations for gravity warping space-time, yet these visualizations are still widely used because they help with the initial understanding of the idea--why, for example, you hold one variable constant when taking the partial differential in another dimension, and what effect changing the step size for the gradient descent has on the ability to find a local minimum.