Cramming is a legitimate way to review learned material just before a big test. It gives students a chance to go back over notes, completed assignments, and supplemental materials which have all of the information needed to help them pass a test.
Students don't retain the information gleaned from cramming just before a test. As soon as the test is over, all of that crammed information is immediately brain-dumped, and is of no use for future applications which require said knowledge.
[P1] Cramming is the best way to study for a test.
Rejecting the premises
[Rejecting P1] Cramming only prepares students for the short term, not the long term.