[petters]

Should be possible to implement cout more effectively since there is no string parsing. I say “should” because in practice it seems to be the other way around. I don’t know why.

[hermitdev]

Been a while since I've looked at it, but pretty sure std::format validates and parses most (all?) format strings at compile time. There should be no runtime penalty.

[vitaut]

There are some fundamental reasons why cout is slower than stdio/{fmt}: https://stackoverflow.com/a/65325727/471164.