Information can be required at any time, any place and under any circumstance. Having crucial information at the time of performing a task can be the decisive factor for its success.
Imagine a situation wherein you attend a learning session to know the operation of a new and complicated tool/software/product. But, the problem arises when the requirement to use it comes after a long time. By then, parts of training are already lost, although you are aware about the tool in general, you lack the intricate knowledge required to operate it proficiently. At a moment like this, a small course, brushing-up the basic facts and functionality of the tool can go a long way in helping you recollect your main training.