My cuban friend "how the f--- is it a chachachá without the words chachachá?"
Keep in mind chachachá came from son and danzon. The Congo pattern is the same for chachachá and Son. The dancers would start shuffling the feet (to the 4&1) of the Tumbao when the intensity of the song picked up but the tempo stayed the same. someone heard the shuffling and came up with songs about chachachá. it was the cuban "Twist" in a way.
To me this doesn't sound like a guajira son (though since I'm not the musician of the song and I'm white) because of the lack of the guitar pattern characteristic of Guajira and the rural feeling and lyrics.
It's like Miles Davis having a song called "Line dance to my country song".