"If you can do burst runs of 15 km/hour, that doesn’t mean you can run a three hour marathon."

Once you're in 3 hour marathon territory, what you can do for 1 mile is a lot more relevant to what you can do for 26.2 miles than you might think. One of the tent poles of effective marathon/half marathon training is to make your race pace into a drumbeat. You want to feel your race pace in your bones. Very effective workouts look like: take your marathon race pace, and run 5 minutes easy/5 minutes hard (~race pace) for 60, or 10 easy/10 hard for 80.

Tesla is talking about burst builds that last for a week. That sounds like very effective training that will prepare them for race day.