You know why?
It's the humor.

Japanese humor is often manzai, or better known as lampshading.
The jokes usually go like this:
>Ordinary setup -> Funny man says something unexpected -> Straight man points out the absurdity of what funny man just said.

This is a very common joke format. What's powerful about it is that it's really easy to execute.
People like Biboo and Gigi have a lot of trouble trying to figure out how to deliver a punchline, stuttering all the way, because western humor is more about creative zingers.
Japanese humor is literally "do silly thing, point out silly thing", anyone can do it on the fly. It may not be the funniest joke ever, but its low creative barrier makes it perfectly suited for long conversations.

Another strength of this type of humor is that it flows naturally into any conversation.
It's perfectly compatible with CGDCT because you can talk about any topic and make it interesting by turning it into a manzai joke.