Just kidding, it's dumb.
Over the past few years you may have heard the term "muscle confusion" thrown around. Especially if you've got involved in any of those as seen on TV programs like P90x. Essentially, muscle confusion is a foolish scam to get you to pay for something that doesn't work. It's a gimmick, a daily cluster of putting random exercises together at different intensities and progression levels to "confuse" the muscles into growing. Whatever that means.
Research and principles like the of the law of specificity and progressive overload principle debunk this theory. Training should improve movement first, then add resistance, then progressively overload these movements to improve strength, muscle growth and endurance. Eric Cressy said it perfectly with the short phrase "chase adaptations, not progressions."
Muscle confusion takes out the consistency factor that's needed for the body to change. The constant changing of different types of workouts at all different levels of progression never allow you to improve and progress. You actually hit your training ceiling much quicker and then just dance around it until you get burnt out or hurt.
A lot of times people wonder why my programs work in three and four week blocks. I like for my clients to chase adaptations. Progressions are fun and necessary to continue progress. But, they must be built-in with the purpose of challenging current and established adaptations.
No matter how well it's sold, don't buy into muscle confusion. It's dumb and has not one scientific reason why it would work for building muscle or burning fat.