I watched them all. Only thing that bugged me was how the catboy said Ifrit.

I think with the idea in mind that they're probably aimed at those with little to no gaming and/or MMO experience, they're very helpful and informative guides. They've got some charm and humor to them, which makes watching them fun. I don't know being adult or late teen means that someone can't enjoy the animated visuals or the cheerful atmosphere. They seem to me that they would be an effective marketing tool. They really don't seem to be intended to go in depth, just be something that someone can use to get their feet under them.