if supplements don't absorb and therefore don't affect health, there's no reason to take them.

You missed the K2 part of his comment though. Both my mother and I have chronically tested incredibly low for vitmain D, both always taken supplements, both never had improvement. A couple years ago, my mom texted me saying she tried a D3+K2 supplement and for the first time in her life tested in range for vitamin D on her panel. I was skeptical but tried it, and have tested in normal range since.