It takes a long time to create useful palaces that have good yield. It is more important in medical school to understand the physiology and explain why symptoms or laboratory findings occur, or the major treatments and how they work, or types of pathologies and how they develop. An astute student should come to the conclusion that exam writers do not and cannot expect students to know everything in medicine, but instead understand the overarching themes and mechanisms and apply them to different situations.
There are a few situations where brute memorization is necessary (basic science such as gene marker names, anatomical names, chromosome numbers, embryologic derivatives, inflammatory markers, much of micro), but the yield of these facts is truly small in medical practice and on some boards. That said sketchy is a useful organizing tool similar to a memory palace and is helpful because the memory palace is already made for you. If you can bypass the time and energy it takes to create them, do it, but be careful to realize you need to understand the material not just regurgitate.