I perfectly remember them also being embedded in DDOS as a Service offers. It's surprising seeing many persons saying an IP is not PII/private. While it may not allow you to "hack" a person, you can very certainly saturate his uplink. I also remember streamers being resolved and targeted repeatedly.
Yeah. If you were decently high ranked in any popular video game at the time, you had to make sure you didn't share a username between Skype/the game, or you'd be DDOSed endlessly.