If people use it and they don't post or comment, it could go dark

No, it just means you wouldn't be counted as 'active' on the site.

It gives a more realistic number of people who are actually using the site, rather than being Facebook and touting '2.96 billion active users' when we all know they're also counting people who haven't logged into the site in 6+ years.

it's a just a post to try and get the numbers on the fediverse up, and attract more users. get those numbers up bois!