Come on!? Have you really run out of teaching ideas already? I think there are a lot more useful things to teach your students before you go scraping the bottom of the barrel of Westen pop music. Why teach this? I take some comfort in the fact that most Korean kids will never have the misfortune of hearing this garbage. It wouldn't be so bad if this Rebecca person was speaking real english, but she isn't. Please, for the kids sake, don't do it. There are other lesson materials out there I promise.

Yes there are better lesson materials out there.

However, it's not entirely useless

"Gotta have my bowl, gotta have cereal"

Many of my students don't know what "bowl" is.

Other expressions I can teach that my students probably don't know

"Gotta catch my bus"
"Kickin in the front seat"
"Gotta make up my mind"
"Everybody's lookin' forward to the weekend."

and so forth.

Also, many people are currently talking about the video.   Enough that it now has 112 million views.  So, it's also useful for keeping students in touch with current western culture.