Cross fit sells because the workouts are short and Americans love to hear they can achieve results without a lot of time investment.
xFit has it's place in today's society and is a program where one can get shredded for the beach. However it has no place on boards like these where serious runners are training to improve times in a specificity sport like running and certainly not advice from hobby jogger times like MacKenzie.
I just knocked home a 100 burpees, snatched 250 and ran a couple 200s at the track. I cant wait to see my marathon time improve from 2:45 with my 15 minute HIIT workouts over the next 16 weeks :)