Grixis Control has very few creatures that attack in numbers (Baleful Strix, Murmuring Mystic, Thorn of the Black Rose), so Tangle's tap-down effect is mostly wasted; Dispel instead protects your crucial draw spells like Behold the Multiverse and Arcane Denial from their Counterspell and Spell Pierce. This is a long grindy matchup decided by who runs out of resources last, so preserving your card advantage engine (Lorien Revealed, Plunder the Trollshaws) is the priority. Keep Moment's Peace and Fog since Murmuring Mystic tokens or Thorn of the Black Rose can still occasionally attack for value.