I love how they tout the ability to earn miles for tax payments, and then the fine print says that tax payments only accrue miles at 0.1%.

I think there is a certain subset of wealthy people who will get this card just to flex and/or keep up with other people who have it, without really thinking about the cost:benefit ratio. The same kind of people who use an Amex Platinum or Centurion for everything even though it leaves buckets of points on the table.

Aside from that, I think the best use case, as Pak suggested, is to top up FOPs to attain a higher status level. But most road warrior types don't have an extra 600k lying around to pay the annual fee, so this segment of the potential market would be very limited. Maybe a handful of very senior executives would be interested.