What about the CRI hype (color rendering index)

So what if lumens are lost? Did you read Luminous flux @ Wikipedia, or the Luminous efficiency function article?

The perception of light by the physical eyes is a biased thing. Different people have different visual acuity and color perception, with the latter being at the forefront of this discussion.

Now I will quote something from Luminous efficacy @ Wikipedia:

Now, if you are to understand that low CRI emitters are made to boast higher lumen figures at the price of lower color accuracy, this could be fine. Let's say that low CRI emitters with higher lumens are not better, just different. It's as respectable as I can be here, because in practice true flashlight lovers end up discovering that their EDC lights are high CRI, while their low CRI units tend to end up being shelf queens. This usually doesn't happens spontaneously, but over time.

If you don't really care about colour accuracy, get some green emitters and see if you like them (example: Osram Ostar Projection PC-green tested, KP CSLNM1 F1), they can provide you maximum green lemons per watt.

:facepalm:

The loss in lumens is very bad and the flashlight gets hot very fast bla bla bla? Are you trying to imply that the flashlight gets hotter with a high CRI emitter versus a low CRI one?

There's only one case in which the flashlight heating would be lower and this is with a low Vf emitter versus a high Vf emitter in a flashlight using a switching driver (buck, boost or buck-boost driver), and in any case the difference would be very veery small, and it has to do with the Vf of the emitter (and not the CRI) because (regulated) drivers are regulated by current flow, and current flow times voltage (Vf) means power at the emitter, and for this reason when the emitter Vf is higher the power at the emitter and overall dissipated power is also higher. So only when using switching drivers, and more than likely using some accurate thermometer to try to measure a veery tiny difference, you could say that there's a difference in heating with low Vf emitters versus high Vf emitters.

And if using a more typical regulated driver (AMC7135's and regulated MOSFET units -linears-), the difference is none for as long as the battery voltage is higher than the emitter Vf, which keeps the driver in regulation, and only when the battery voltage goes lower than the emitter Vf the current flow starts diminishing and so does the flashlight heating. And only when using unregulated drivers, you could say the heating is higher when using lower Vf emitters, as the increased battery to emitter voltage difference causes higher current flow and power output.

So in essence, your argument is wrong.