"Best case" is that you then follow with a challenge trial and demonstrate actual immunity much faster than a conventional vaccine, leading to months shaved off the time needed to immunize the general population. That clearly has value, particularly given that people are still dying at a high rate in the US and much of the developing world.

Now... does that mean this is going to work? No idea. But these folks aren't dummies either. I think it has a shot and is worth trying as long as everyone involved (e.g. these are all university scientists) has a clear and solid understanding of the risks.