The theory of learning styles states that people have distinct learning styles (visual, written, auditory) and says that people learn better/best, when they receive instructions that match that learning style.
Book - Make it stick.. the science of successful learning argues that while people have preferences for certain ways of learning, they do not learn better when the instruction matches these preferences. They present a 2008 meta study, which showed no evidence for the theory of learning styles. However, the review showed that instead of the learners preferences, the instruction should match the nature of the subject, which leads to all learners learning better, regardless of preference.
Pashler, Harold & Mcdaniel, Mark & Rohrer, Doug & Bjork, Robert. (2008). Learning Styles: Concepts and Evidence. Psychological Science in the Public Interest. 9. 105-119. 10.1111/j.1539-6053.2009.01038.x.
The book goes on to highlight actually valid differences in learning, in particular "mindset" (described by Dweck), intelligence, and how we structure the information we take in ( e.g. Rule Learners vs Example Learners)
Individualism like the one provided by learning styles often gets adopted (even though no scientific evidence exists) in order to provide further justification for one's behavior and its outcomes. In certain areas, this individualistic approach is misguided, e.g. see The method of tidying up does not depend on your personality type