Yeah - I've had plenty of steak tartar, and it is delicious. The difference here is that with steak tartar, you know you are eating raw meat. With Sous Vide, you assume you'll be eating safe meat. It is doubly important in sous vide to reach pasteurization because of the extended period of time spent in the bacterially friendly temperatures.

Its a good point about the exterior surface, but the blog post also shows him cooking a hamburger.