You're correct that LEDs aren't actually producing light like a hot black body radiator, but we still measure their shade of white using that scale as a reference. This is called the "correlated color temperature," which you'll almost always see abbreviated to CCT. It's not "this light was produced by a black body radiator at 5000K", it's "this light is perceived by the human eye as the same color as a 5000K black body radiator. Where does the human-perceived color fall on the Plankian locus?
As far as cheapness, yes and no. The swimming pools that I've designed tend toward the more blueish whites and low CRI because they have a light level target to hit and that's the cheapest way to do it. With the exception of some small residential pools, they aren't trying to make a warm cozy feeling, they just want it to be bright enough to meet the requirements for safety / code / IES recommendations / NCAA requirements, etc.
But a lot of lighting isn't done that way where you're determining the layout and quantity of lights to hit a target level at lowest cost. It's much more common that you pick the color temperature that you want it to look like and you buy that regardless of the exact light output.
LED bulbs at the store have a Lighting Facts label that tells you the color temperature and how bright it is, and the different CCTs of a given brand bulb will cost the same. Yes, you get more light out of the more blue one, but when you're getting bulbs for you're house you'd never say "Get the 4000K version. It's an extra 100 lumens, so we can light the house with 17 of them instead 18 and save a few bucks."
Interestingly there are cultural conventions to this too. In the US it's much more common to see the warmer color temperatures in homes and even in offices. In Asia and India you'll encounter a lot more blue.
https://en.wikipedia.org/wiki/Planckian_locus
As far as cheapness, yes and no. The swimming pools that I've designed tend toward the more blueish whites and low CRI because they have a light level target to hit and that's the cheapest way to do it. With the exception of some small residential pools, they aren't trying to make a warm cozy feeling, they just want it to be bright enough to meet the requirements for safety / code / IES recommendations / NCAA requirements, etc.
But a lot of lighting isn't done that way where you're determining the layout and quantity of lights to hit a target level at lowest cost. It's much more common that you pick the color temperature that you want it to look like and you buy that regardless of the exact light output.
LED bulbs at the store have a Lighting Facts label that tells you the color temperature and how bright it is, and the different CCTs of a given brand bulb will cost the same. Yes, you get more light out of the more blue one, but when you're getting bulbs for you're house you'd never say "Get the 4000K version. It's an extra 100 lumens, so we can light the house with 17 of them instead 18 and save a few bucks."
Interestingly there are cultural conventions to this too. In the US it's much more common to see the warmer color temperatures in homes and even in offices. In Asia and India you'll encounter a lot more blue.