These Boltzmann brains people hypothesize are us in a sense. But it is billions of Boltzmann brains suspended in a low entropy universe. That’s what is so puzzling.
How did universe acquire this capacity for initial low entropy with billions of Boltzmann brains in them?
Surely the only way we know for there to be a simulacrum of final cause is through evolution.
And for there to be evolution of a trait such as initial low entropy with intelligibility in a universe there has to be re-production of universes. Universes giving birth to a better universe.
And that brings us to the purpose of intelligibility in a universe. Intelligibility surely must play a part in making better universes. As a trait of a universe it is very likely to aid its reproduction and survival.
Some form of super intelligence (singularity) will inevitably(?) arise in this universe before its heat death. And it will, out of a decision to prevail, will engage in creation of universe(s). It is this singularity that people call God – the alpha and omega of the universe.
The real question is whether we can influence such a god so that the next version of the universe will have better versions of us. And whether it would make our next versions worser off, if we try to stop it from becoming (a la Roko’s Basilisk).