@2com For lighting houses and offices the current SPD chart perhaps makes sense. The people who design lighting plans are mostly interested in the observed "color" of the light. Efficacy is a different parameter that they can view separately.
For growing however, we are interested in photons.
I never really understood why they draw these charts like that though.
It's just like those PPFD matrices where they measure the light with no surrounding reflective walls. Those are really quite useless. More than half of the light will normally come back through reflection. Or you have overlap from the lights next over in a big room.
Or for that matter sphere tests. For instance the Diablo is supposed to hang at 24". Ledgardner showed a PPFD matrix of the QB648 and this illustrates that up to 29% of the light is absorbed by the walls with of those two boards in a 2'x4' tent. A single QB in a 2x2 tent loses over 40% of the light on the walls.
So you buy a more expensive light so it produces light very efficiently (according to a sphere test) and then in reality you need to hang it quite high above the plants, which results in massive losses of that efficiently produced light. You might as well buy a cheaper less efficient light that can hang a bit lower down to the plants and then not put so much light on the walls instead.