Their power figures for the stations are way off. RX is definitely much lower than TX. The largest power consumer is the power amp not the ADC.
I think this is a desktop card they have analysed, and these are non optimised for power consumption.
Also this seems to be only for directed packets, and "idle listening" is mostly with non directed packets. Carrier sense is only required before a TX when medium contention occurs. Here also RX can be killed after preamble detection.
So while there is an advantage, the benefit don't seem to be worth the effort, especially as the device is not 802.11 PHY compliant anymore. It can work with older stations, but this is not guaranteed. Those M-preambles before the frame violate the timing.