So given the reveal about Agatha, I think the meaning of the yogurt commercial is that she's feeding off Wanda's power somehow.
-"Snackin' on Yo-Magic" = "snacking on your magic" -"The snack for survivors": in the comics, Agatha is a survivor of the Salem witch trials, and in ep1 she mentioned her anniversary is June 2nd, the day the first woman was tried and convicted of being a witch in those trials -The shark's music in the commercial is similar to (though not EXACTLY the same as) Agatha All Along -"Agatha Harkness" anagrams to "Agnes tha Shark" with an A left over