the number one reason to carb cycle is because you are so depleted of glycogen in your muscles, you become stringy.
adding a high-carb meal day or two can help improve your glycogen stores and strength for heavy exercise days as well as give you a more plump appearance, but adding creatine to your diet should be your first step in order to pump and pLump your muscles, not increase carbohydrates if you're going for muscle pump.

another reason to carb cycle is to mix up your body's metabolism, so it doesn't adapt to your current diet. Your body will adapt to your diet just like it will adapt to your workouts, so mixing up your macronutrients is a great way to shock the body temporarily.

I think carb cycling should be done only after weeks of tracking your macronutrients and knowing exactly how to increase it a little bit without gaining body fat. in other words, you will easily be able to see how your body responds.