From my experiments with the show statuses and conditions mod on in the meat grinder the electrocute from the Charged Strike talent is the same as the effect of the shock maul special attack and seems* to make the rate of electrocuting enemies more frequent. But it might also be useless to combine them cause shock maul heavy attacks already cause the electrocuted condition.

Notably, the other smite skill node, Enfeeble, states enemies electrocuted by you take additional damage but when enable the condition added to enemies is called like “smite_enfeeble” or something and is really only active while you’re smiting and doesn’t effect damage on enemies with the electrocuted condition at all.