In training (as in life) not everyone is created equally. Everyone absorbs and processes information differently. Some people are learn best by listening, some by reading, some by doing. It all comes down to their individual learning style.
Knowing the difference between learning styles is important if you want to give your team of learners the best chance of retaining what they learn so they can use it on the job. Plus, offering appealing training opportunities is much more interesting and makes happier learners.