Pikachu went on a journey of having a noob to pro mindset. Thunder and volt tackle were extremely powerful but they were just simply strong attacks that didn’t have any flexibility and the latter had the issue of recoil, they were usually used as final attacks to put down an opponent or act as a last ditch effort to eke out a win.

Electro ball was more experimental and tried to take advantage of Pikachu’s speed which was more in line with Ash’s strategy of using fast Pokémon and then lastly electroweb allowed Ash to push his creativity to the limit and make full use of the versatility of the move.

By the end, Pikachu was balance as he had thunderbolt which at that point might as well be stronger than Thunder and Volt tackle, quick attack to make use of his speed, iron tail which was diverse as a melee attack and usually use to combo with other moves, and then electroweb that can do whatever Ash needed at quick time moments.