>This is not physics, just some number coincidence in the metric unit system
It's not a coincidence. The meter was (historically) intentionally defined as how long a pendulum is that swings in 2 seconds. When you do that, g = pi^2.
>The fact the author calls this a "wonderful coincidence"
The author doesn't call it a wonderful coincidence. The author asks the question of whether it's a wonderful coincidence or not, and comes to the conclusion: no.
It's not a coincidence. The meter was (historically) intentionally defined as how long a pendulum is that swings in 2 seconds. When you do that, g = pi^2.
>The fact the author calls this a "wonderful coincidence"
The author doesn't call it a wonderful coincidence. The author asks the question of whether it's a wonderful coincidence or not, and comes to the conclusion: no.