The reason I like optimization is because it lets players feel more epic. They get to face off powerful enemies at lower levels if they're optimized. They can survive more difficult encounters, traps, and overcome tougher challenges earlier on. And when they finally reach Tier 4, they feel like gods and can face off against actual gods and have a fighting chance (Tiamat or Vecna, for example).
Just because a party is optimized doesn't mean that they should steamroll over every "challenge" they come across. Sure, let them and their strength shine often enough that they feel that their hard-earned optimization was worth it, but also let them feel challenged when it counts. Otherwise, in my experience, combat becomes a boring slog of "when are we finally going to defeat this enemy?" instead of a true battle to the death.
So, I would choose a 4th option "Turn the power-dial when it matters, and leave it at base when it doesn't." If you want to make an impression to your optimized players, turn up the dial. If not, let them breeze through it. (My optimized Icewind Dale party that was only level 6 survived a near-deadly encounter with an Ancient White Dragon that they accidentally pissed off. No, they didn't kill it, because that would be ridiculous, but they did manage to not die through a mixture of ingenuity and optimized mechanics. They felt awesome and worn out after that, which was my goal.)