I mean, greater brevity in theory, but having used both s-expressions and JSON for config files, I can tell you that the s-expression version ends up noticeably

I mean, greater brevity in theory, but having used both s-expressions and JSON for config files, I can tell you that the s-expression version ends up noticeably less verbose and noisy in practice. > This despite the fact that that notation is decades older than almost every other syntax out there and yet still lost the popularity contest. Beyond some minimal level, quality and popularity aren't all that heavily correlated; something not becoming popular tells us almost nothing about it.