Freight is easier than passengers due to safety concerns (and G-forces). But saving 70-80 minutes on an Abu Dhabi-DXB trip is probably not enough to make that viable. You could already get a ~40-60 minute trip time with traditional rail (which would be cheaper) and I don't know where the demand for that extra 30 minutes saved comes from in Cargo. Passenger transport would definitely be a market but has much higher hurdle. You either have to go through the sea (very long bridge?) or will have some turns in the route, in which case I don't see how they can achieve those speeds.
For cargo to be competitive, this would have to run over long distances that have a lot of cargo traffic, e.g. China-Europe. That would definitely be a killer application but also extremely hard to get approved in all countries.