>>44361662Pretty much, Charizard can deal some insane damage, and is allowed to switch out after attacking as setting sun is way easier and safer than using a boosting move, also, Blastoise lacks coverage and cant touch most water types.
+2 252+ SpA Blastoise Hydro Pump vs. 0 HP / 0 SpD Mew: 297-349 (87 - 102.3%) -- 18.8% chance to OHKO
252 SpA Choice Specs Solar Power Charizard Fire Blast vs. 0 HP / 0 SpD Mew in Sun: 535-631 (156.8 - 185%) -- guaranteed OHKO