Think of it as pieces of kanji. Wanikani deconstructs kanji into smaller pieces so that you’re better able to memorize the kanji. This will be especially useful when distinguishing very similar kanji:
俊 酸 駿 唆
Notice how the left side differentiates in each kanji. Those are actual radicals on Wanikani. By knowing them as individual pieces, you’ll be able to distinguish the kanji better. Also, take into consideration that I did not use one of the most confusing list of kanji
Hope that helps!