How in heck does ANY gadget bleed off the high heat implied by a demand for 90º C tap wire?
The issue is: does the fixture back-feed HEAT up the line to the point that the Romex is cooking?
Romex is THHN wearing a sweater. That's why its internal conductors are so strongly de-rated.
Having played with ancient lighting taps, I can assure you that they turn to dust.
The thought of an insulation displacement connection = point of spot resistance = hot spot. Terrific. Just what the patient doesn't need.