It probably works just fine, but whether it makes sense for you depends on how you use hot water (and how much hot water you use.) It's standby losses are probably much lower than an atmospheric drafted tank, and it'll never short-cycle like a tankless, so it's probably comparable in net efficiency to a non-condensing tankless, but would support more rapid tub fills than a tankless with twice the burner, with none of the quirks of a tankless. It's probably a dumb 2-stage burner rather than the more sophisticated modulating controls of a tankless too.
By having a non-modulating burner greater than 75K they don't have to run an EF test on it, and can present it's steady-state combustion efficiency as it's thermal efficiency. At 80% steady-state it's comparable to an atmospheric drafted standalone's combustion efficiency, but since it's using a tankless type heat exchanger and a pump rather than a center-flue heat exchanger, it doesn't have nearly the parasitic loss. It would likely score in the mid-70s in an EF test and hit near that over a wide range of daily use volume, which isn't that different from the typical as-used efficiency of an 82-86% efficiency tankless (which never quite meet their EF numbers in the real world due to short-cycling losses on short draws.)