Well, fire does not shine by black-body radiation. Lamps try to emulate a black-body because that's what color standards dictate and labs test against, but fire has a very bad color resolution. (By the way, daylight isn't also like black-body radiation, but it's much closer than fire.)
Personally, flickering makes me ill. I am used enough to 120Hz to survive it, but any other frequency is bad. Also, the 6400K LEDs look way too blue, much bluer than the Sun. That may be because I have a relatively rare kind of color blindness.
huh that's really interesting about fire's emission spectrum!
regarding 6400k - even assuming the sun's spectrum matched the black body spectrum of its surface temperature, its surface temperature is closer to 5770k. but even taking that into account, its spectrum doesn't quite match 5770k in space - and the atmosphere changes it even further. https://en.wikipedia.org/wiki/File:Solar_spectrum_en.svg
I really don't know how much of that change us humans can perceive, but my thinking is that 5000k is probably closer to the center, at least. it might be more of a saturated color, though, since the spectrum is more pointed vs the very flat but spikey spectrum in that plot.
Personally, flickering makes me ill. I am used enough to 120Hz to survive it, but any other frequency is bad. Also, the 6400K LEDs look way too blue, much bluer than the Sun. That may be because I have a relatively rare kind of color blindness.