I honestly don't know how it actually works.
How often can it proc?
Does it trigger when you re-apply electro/hydro?
1000 EM = ~10.000 Electro Charged ticks, it's pretty solid depending on how often you can apply it.
but I'm not sure how it actually works as both Hydro AND Electro are on the enemy when you trigger that reaction.
It could, in theory, mean, that the correct character is always triggereing the reaction. Unlike what could happen with Melt/Vape.
In Abyss, it's actually a rather "cheap" way to get results when you team up with Anemo.
10k+ every 0,5 seconds is quite potent, especially if it's offside damage.
People play with Albedo who hits for 20k every other second or so and think it's super strong... so.
The question however... if you also use Anemo... what EM value is used for Electro-charged when Electro gets swirled onto hydro or vice versa. Does it use the EM of the character who applied the initial Electro Aura? Or does it use the EM of the Anemo user? But he is technically not causing the reaction because it's already causing "Swirl" as a reaction...
Did someone actually bother to investigate? I never heard "IWintoLose" or other youtuber talking about it.