At high concentrations, its still fucking awful for us. Easy to forget that the atmosphere is still only 21% Oxygen and 78% Nitrogen. Even setting aside the risks of fire and explosion at higher concentrations, this highly reactive substance degrades the nervous and musculature system.

You wouldn't want to wander around in a fully oxygenated environment for the same reason you wouldn't want to drive your car through a lake of gasoline.

I have no serious knowledge about it, but for the thermic aspect I can't imagine it working in any way.

Your body will try its best to keep its core temperature constant. So you won't really cool your cells down.
In this process it will burn even more fuel to produce heat, so quite the opposide they want to archive.

Grift. Same for blood boys. The meritocracy is just a lie, the rich are dumb as shit like everyone else.

Something I learned recently on another topic: The human body is 67% oxygen by atomic mass.

You don't breath poison. You are poison.