On some Regieleki sets, Electro Ball is quite good. For example, Agility sets make Electro Ball extremely powerful (since Agility doubles its Speed).
With Timid, full EV investment, and at +2, its Speed hits 1096. This is pretty fast, though Dragapult still survives it at -1. While Toxapex is OHKOed by it, Thunderbolt and Thunder Cage also OHKO.
252 SpA Life Orb Transistor Regieleki Electro Ball (150 BP) vs. 252 HP / 4 SpD Toxapex: 585-689 (192.4 - 226.6%) -- guaranteed OHKO
252 SpA Choice Specs Transistor Regieleki Thunderbolt vs. 252 HP / 4 SpD Toxapex: 408-480 (134.2 - 157.8%) -- guaranteed OHKO
252 SpA Choice Specs Transistor Regieleki Thunder Cage vs. 252 HP / 4 SpD Toxapex: 360-426 (118.4 - 140.1%) -- guaranteed OHKO
I feel like both Thunderbolt and Thunder Cage outclass Electro Ball. Its just really situational. Thunderbolt is reliable, while Thunder Cage can wear down your opponent.
Electro Ball does have its perks though. Since Regieleki is so fast, Electro Ball, especially at +2, will do more damage than both Thunder Cage and Thunderbolt in some situations. Again, it's really situational.
Hope this helps! :)