I'm thinking BMW must be selling enough of the F800ST to get Honda's interest. That said, I don't know who the target customer is for this bike. It may make sense in Europe where there is such thing as a motorcycle commuter, but is there really such a thing in the US?
I see a bunch of shortcomings compared to the BMW -
1) Seat height - The Honda is not short, the website says 31.7 inches. The BMW can be tailored - it comes in the stock (about 32" - too lazy to look it up), with a low seat, low suspension, or both. The BMW can be had with a seat height down around 29" if desired.
2) Weight - the Honda is more than 100 pounds heavier. BMW claims 425lbs (again, from memory). I'll assume that's dry, but still in the range of 460lbs ready to ride.
3) Power. The BMW has 85HP in a light middleweight package, the Honda has 70 in a heavy middleweight. I guess there's a reason Honda is calling it a luxury tourer rather than a sport tourer.
Honda does have a lower price - the BMW is about a grand more dear, and that doesn't include hard bags.
I can see the BMW selling to riders of smaller stature that want a true sport tourer. But I can't see the Honda as appealing to those same folks - too big, too heavy, too modestly powered. Though perhaps a Vstrom or Kawasaki Versys with a full Givi setup makes more sense on a price/performance/utility basis than either the Honda or BMW.