Volt Tackle complements pikachu's attack Stat being higher than SPattack. And a light ball makes it have that double damage (Stab will be there too) making the move... By far better than Thunderbolt. Though I would put Volt Switch on Pickachu anyway. If you want pikachu to be a Sweeper CHOSE VOLT TACKLE, and make sure you have a Pokemon with healing wish on your team. Or wish in general.