Likewise. It can’t be much different from e.g. the old lighted tailcap implementations. I.e. cell current lights up the aux. LEDs, albeit through an LDO regulator, but that makes no difference really to current consumption compared with the simple bypass resistor on the earlier designs, except the output is stabilised, so current should not vary much as the cell discharges.
If they can change colour based on cell voltage, that would be nice, but I’m not sure that is what is being offered here.
At the end of the day, keeping some aux. LEDs glowing takes a small continuous amount of power. Perhaps not a problem with a x3 18650 torch, depending on brightness, but certainly for smaller ones. The BLF X5 is such an example, although only having one LED in the tailcap the 14500 cell capacity is insufficient to keep the tailcap glowing for useful periods, hence disconnected on mine.
Just lighting up the switch, as on the Q8, takes minimal current, given the x4 18650 capacity, and is a useful feature.
It is a neat and clever design, for those who want it.
I have a few torches that have a switch LED which indicates cell state of charge, e.g. blue or red, when the torch is switched on. Or can be left on permanently. One even blinks red when off, to warn of low cell voltage. I find this useful. (Nitecore designs)
In other words, I like these as indicators of cell voltage, or as a way of locating the torch in darkness. Putting them in the head, rather than the tail, is an improvement I think, and perhaps the best way in e-switch designs, although just lighting up the switch in two different colours is good enough for me, and should take far less current.
Not enough pins on the chosen MCU though I think.