They have a frontlight rather than a backlight. And there's quite a bit of evidence that colour temperature and brightness both have a big effect. But I broadly agree that it will still have an effect. I use my kindle without the backlight and with a warm coloured lamp.

I'm not dismissing it having an effect. But isn't it probable that the light profile would be somewhat different for an actual monitor and a back/sidelit eInk dislay? If so, the effect may differ as well.

Front light, I agree, would probably have a different spectral profile.

Technically it’s a front-light, shining on the front of the screen from the side. But the nature of the eInk is such that you don’t have to use the built in light, you could just turn in your normal lamp.