Why is Veil of Discord unpopular right now?

It really seems like a pretty solid item for the early-mid game, but it's ranked #132 in item popularity and was rarely seen at TI10 despite its 53% win-rate.

• It's a flat 18% damage boost to all spell damage, including physical and pure damage
  • Spell damage is really strong early-mid game when most heroes have low HP pools, lower magic resistance, and fewer dispels
• It's got a huge AoE with no travel time
• It lasts 16 of every 22 seconds with low mana cost
• Nice 1.75 mana aura for owner and allies for early sustain
• Total cost of 1525 gold with a decent buildup from laning stage for many casters heroes
  • Ring of Basilius + Crown + Recipe (650g)
• Can maybe bring some tanky strength heroes down into magic bursting range
  • Weakened have ~847 HP for every 1000 HP, or basically 153 free spell damage for every 1000 HP removed by spell damage

It really doesn't seem like all that bad an item, particularly for a Pos. 4 and maybe some Pos. 3s. Are we sleeping on this, or am I just stupid herald garbage