Yes to broaden the spectrum, but with this mix of spectrum how much of it is actually used by the plant and how much wasted, compared to running a garden using just one spectrum ie 3000k. Maybe a question for
@robincnn HLG since they are designing these boards and should have a clear understanding.
Cheers
Hold on there. You're making an incorrect assumption; these boards are NOT just one slice of the spectrum; they're a mix of Spectra from blue to red. The color temperature should be thought of as an AVERAGE.
They're producing 'white' light (imperfectly, hence CRI values), so all Spectra in the visible band are represented. There's more of some wavelengths than others and it so happens that these chip's output matches up quite well with what we know about the plant's needs, aka PAR. This is one source of their efficiency and effectiveness at growing plants.
The other source of their efficiency is how well they convert Watts into those Spectra.
Don't get caught up in the idea that they only produce light in the band of the color temperature; if they did that, they'd be bright yellow or orange. This is what first generation LED fixtures did; blue and red diodes to match chlorophyll adsorption profiles. Turns out they didn't work so well, because the plants need at least some of everything in visible light.
The board's light output might be warmer or cooler, but all the colors are in there.