It is primarily a political manifesto, as he presents it as an alternative (cheaper, faster to build, faster at moving people) to CA's HSR project.

However, in my view, there's nothing that makes Hyperloop and CA's already started HSR project mutually exclusive. Hyperloop just isn't a valid alternative. It does sound awesome, though, and it should be built, too, because - why not? Its cost to build is low enough that private investment and a public private partnership to get it to share rights of way (where necessary / convenient) with HSR, to even share stations... I mean Hyperloop could be conceived of as the express line from LA-SF - a complementary technology, not an alternative. Even if we had Hyperloop, there are still a number of great arguments for having HSR too. And the fact is, we don't have Hyperloop, it's a completely untested, unproven technology. We do have (a detailed plan, approval, and some funding) for HSR. So we should build HSR, check out Hyperloop, and if it's actually feasible we should do it too, and connect them.