[darklajid]

Because it takes nothing but an openssl installation (or similar) to generate one?

Anyone can control a (root) certificate - the problem is getting others to trust it. Legitimate use cases might be: You want to intercept (and decrypt) traffic going from your local computer to SSL/TLS endpoints (affects only you) for example. Less clear cut / nice example: Company wants to read your traffic and therefor deploys a cert like this on your computer, now can snoop on anything you do, https or not.