Is that it addresses a civic matter as a physics problem.
Is that it boasts about its costs relative to high-speed rail with none of the difficult last-mile considerations that the latter has accounted for. Hyperloop goes from Sylmar to Hayward, not from Los Angeles to San Francisco. And do consider that ordinary underground trolley tunnel in San Francisco currently costs about one billion dollars per mile.
Is that it is a neat solution to the wrong problem. The problem is that assembling a right-of-way in a modern state is near impossible, that aligning literally thousands of stakeholders takes a good deal of time and money. The technical challenges of high-speed rail are not the reason that high-speed rail doesn’t exist in California. The obstacles are the political and democratic processes that, for better or for worse, force all parties to cooperate and compromise, which are grindingly slow and often result in no construction at all. I would like to see Elon Musk address these problems rather than draw pictures of a vacuum tube between the northern San Fernando Valley and the southern half of the East Bay.