It seems to me a nicer shape and finish than most AAA size lights. It might even be second to the SS-5039 (which has little else in its favor).
The 219C does not necessarily give it lower output than it would have with an XP-G. Unlike a regulating driver, a boost driver will put out more charge at the lower voltage. It is even more efficient with a smaller difference between the input and output voltages and will put out more energy with the Nichia’s lower forward voltage. The fact that the measured efficiency is low is probably due to a less expensive driver or stray losses.
A third generation Osram Oslon Square might have done even better. 3rd generation Oslon Square, a 5000K 70CRI led tested Its forward voltage at low current is even better than that of the Nichia.