That helps, but component rendering can still take a long time, so if you have a lot of them you are going to want to take advantage of shouldComponentUpdate
The article is talking about optimizing VDOM generation, not DOM manipulation.
The article seems to muddle the two, e.g., after showing that the method to render virtual DOM elements has been called for each cell it says:
> React’s whole thing is that it doesn’t do unnecessary DOM manipulation, but clearly it is here. What gives?