Most of you will have a dozen or more jobs in your lifetime. Some job changes will also mean a different career. Switching jobs is hard enough, career changes can require years of training and acclimating just to be at the same level you were previously.
Formal education and training is an excellent way to prepare for a career, but like all things there are strengths and weaknesses. For example, in this class you've learned the theory of digital marketing but very little of what its like to work as a digital marketer.