Whether a course is worth paying for, what one buys you, and what it does not.
Yes, and the real question is what the degree adds. It does not replace the exam, it does not exempt you from it, and it costs a great deal more than standalone preparation.
TrainingNothing in the qualification route requires a course. Whether skipping one is sensible depends almost entirely on how much of the syllabus is genuinely new to you.
ComparisonThree of the names people compare are not competitors at all. Two of them run the exam. The rest sell preparation for it.
TrainingNo rule says you must take one. The honest answer depends on how many of the thirteen subjects you have never studied.