I would still run cat6 as if I was going to use smart devices. You're already inside the walls.
And unlike the bricks which you have approx 1 per device, with outlets you need too many of them.
On the other hand, you could buy a single beefy converter (something that could manage a few amps) and then pass 5V DC cable along the regular AC wiring. Not sure about the efficiency of that, though.