The idea behind the new naming system was that instead of badging cars based on displacement (an A4 2.0T, for instance), it will instead badge them based on horsepower. But unlike Jaguar-Land Rover, which will simply put the rounded horsepower number on the back of the car, the Audi system uses two-digit numbers to represent horsepower ranges. This system was to help distinguish more powerful and prestigious vehicles in a world of gasoline, diesel, and soon electric and hydrogen machinery. However, we had some concerns about how confusing it might be, since each number covered inconsistent ranges of power, and the spread of numbers wasn't consistent either.
In Europe, there are many gasoline and diesel models of similar displacement, but differing horsepower and performance, so having a better way to differentiate them all could be useful. But in the United States, there's usually only one or two gasoline engines available per model, each with distinct differences in power based on displacement. Plus, the larger, more powerful engines are already broken up with the S and RS lines, and any alternative-fuel vehicles can be distinguished simply with "e-tron" or "h-tron" depending on fuel.
Overall, we find this to be a sensible decision. As mentioned in the post explaining the badging, we had a hard time following it. There is the possibility of some confusion between markets, but since people aren't deciding whether to buy European-market or American-market versions of Audis, the odds are fairly slim.