Late-game Town Enhancement.

No, it's not a joke. An Elf will definitely take Tactics, but even if you counter it with your own Tactics, the Dancers will reach the target with their aura and boots. The damage difference can only occur if the formation allows you to "wedge" into the enemy troops. And allowing this against an Elf is a sign of incompetence.

I agree with this formulation: Tactics increases the options! Both the Elf and the Demon will reach the target. But the variability of their attacks will be greater if you don't take Tactics yourself. Is that unpleasant? Yes. Is it critical? Not necessarily. Specifically against the Elf and the Demon, I would regularly take Tactics for the Elf Archer - more variety + forcing the enemy to wear blue boots.
But I would periodically alternate it with Cold. As for some kind of universal upgrade,

The essence of Tactics through elements is to strike rarely, but accurately.
Again, a little arithmetic. Let's consider the damage from the Witch's attack (by the way, not the most damaging stack for the Elf Archer; Dracols or Lizards will deal more damage) against the Centaurs who came to attack with their hooves, even without Cold.
Witch's attack damage: 23*2*1.8=82.8
We shoot them, of course, at the opposing element, i.e., +200% damage. Total: 248.4
The Centaur stack has 140 HP, and the Fury has 400. This is enough for 47 damage absorption. Never mind calculating, the Centaurs fall with one shot.
This is the point: with this upgrade, the Elf Archer is very random-dependent. If you're lucky with the elements, you eliminate stacks. The exception is Cyclops; you'll have to attack them with a large group. It is advantageous to attack damaging stacks when the elements add to the damage. You need to attack the Cyclops AT THE RIGHT TIME; often, this right time doesn't come immediately, and sometimes it doesn't come at all because it's too late.
As for the hero's build, much depends on the Lucky Charm and the presence of a Silence spell. With Silence, it's somehow not effective to attack Centaurs, I agree. Most likely, you'll deal decent damage, but not completely. However, this immediately raises the question: if your opponent has taken Silence, why aren't you playing as Dark? After all, one of the most important aspects of fighting an Orc is to torment him with the question, "What are you going to Silence?" But that's a completely different topic. The main thing is that the Elf Archer has stacks that, with elements, can eliminate a damaging, but not very thick, stack of Barbarians in one turn.