From my experience there is a vast difference between learning and understanding.
Bearing in mind that I did my exams 10 years ago, I always felt that the content of the exams was not always related to flying practice (with the exception of R/T and Nav.). There was also an attitude among some of the more mature pilots that 'well, we had to do them so why shouldn't you?'
For this reason I have always suggested the use of the example books in order to 'get through' the tests.
Therefore a 'crammer' course might help get these tests out of the way and give you time to learn to fly and to understand matters applicable to your flying practice.