It has three modes of operation: hull, hydrofoil and flight in ground effect. So it can operate as a slow boat, a fast boat or a ground effect plane. I imagine in bad weather it would switch to a slower mode.
Bad weather usually means big waves as well, so that complicates "just go slower" particularly when it comes to the foil mode. This is what's killed the practicality of previous ground effect aircraft but perhaps they've found the right niches for this one.
Previous ground effect craft absolutely were killed by their poor wave tolerance. That's where our hydrofoils come in. 5ft of wave tolerance through the harbors and in takeoff and landing. Means we can operate with very high confidence and high utilization in most markets.
You mentioned not needing reserve energy because you're able to land anywhere along the flight path. Does that mean you can safely land and float in waves higher than 5ft, even if it isn't necessarily pleasant for passengers or good for the vehicle?
With regard to waves you'll have a much harder time in slow modes as compared to WIG. Soviet (large) ekranoplanes could take off with 1.5 and continue flight in 5 meter waves. Gale force winds is another story.