From the maufacturer's website:
How efficient is the hub?
Very efficient! More efficient than a 1x setup and as efficient as a 2x setup. Compared to a 1x, less cross chaining is required, sprocket and chainring sizes are larger and thus chain tension, crank and hub bearing losses are lower. Compared to a 2x; the fact that the 0.7 ratio of the hub still uses the large chainring in front, results in 30% less chain tension and thus lower chain, crank and hub bearing losses. On top of this you will experience that you will use the Classified hub much more frequent than a normal front derailleur, this means that in practice you will have less cross chain losses. The hub does not have any additional losses on in the 1:1 ratio, and is designed to have extremely low losses in the 0.7 ratio which are completely balanced out by the big chainring and straighter chainline by using a Classified setup.
That looks to me like cod-science which is deliberately intended to deceive. Note the difference between:
"The hub
does not have any additional losses on in the 1:1 ratio"
"
is designed to have extremely low losses in the 0.7 ratio which are completely balanced out by the big chainring and straighter chainline"
Similarly, "30% less chain tension and thus lower chain, crank and hub bearing losses" sounds great, but is meaningless without knowing the amount of Watts which those losses involve and their overall significance.
"in practice you will have less cross chain losses" - I suspect that there may be less cross chain losses *averaged* over the course of
some routes, depending upon how hilly/mountainous the terrain is.
There is no substitute for rigorous scientific measurement of the comparative losses, and that is conspicuously missing from the marketing.