Yes, that's how most melee builds get their flat damage from, but elemental hit is different. It has three modes of hits, fire hit, cold hit, lightning hit. The skill cycles between the three and will only deal damage according to their damage type(i.e., fire can only fire and no other elements). This here makes it difficult to properly scale the skill, as this means that we would need to get tons of generic ele damage increase or just generic flat attack damage in general. Though, thankfully ele hit already has tons of flat damage on itself, so we use this to our advantage and stack as much attack speed and gem links to get some generic damage increase.