writeln!(io::stdout()) vs println

As others, I've greatly enjoyed being able to compare your solutions to my own as I (slowly) go through AoC 2018. Thank you!

Is there a reason that you seem to prefer [`writeln!(io::stdout())`](https://github.com/BurntSushi/advent-of-code/blob/225aa2acbc953905ff696765868694a3ff40c525/aoc07/src/main.rs#L94) to `println!`?