The description of sacred flame reads (emphasis added):
Flame-like radiance descends on a creature that you can see within range. The target must succeed on a Dexterity saving throw or take 1d8 radiant damage. The target gains no benefit from cover for this saving throw. (Player's Handbook, page 272)
Meanwhile, the opening paragraph describing cover reads (emphasis added):
Walls, trees, creatures, and other obstacles can provide cover during combat, making a target more difficult to harm. A target can benefit from cover only when an attack or other effect originates on the opposite side of the cover. (Player's Handbook, page 196)
Given that the first sentence of the description of sacred flame already explains that the effect originates above the target (as opposed to traveling from the caster to the target, which one might presume to be the default), why is it necessary to explicitly state that the spell ignores cover? So far I haven't found any other spell in the Player's Handbook that uses similar language.