Yuanwu's annotations (not included in this translation) say a lot more about what the case actually means, the "pointer" isn't as useful for decoding the meaning of the conversation.
This question is about Prajna (般若）, an evil RELIGIOUS BUDDHIST term! Not wisdom in general. It's discussed in more clear and straightforward detail in the Prajna-paramita sutras, which are the Freshman, intro-level textbooks of the doctorate-level discussions you're reading.
If you just read this and think about wisdom, it's illogical. But for the Buddha-Mind School, Prajna is talked about almost as much as Buddhaness. (Incidentally, the hindu word "Zen" is rarely ever mentioned.)
舉。僧問智門。如何是般若體（通身無影象。坐斷天下人舌頭。用體作什麼）。
A monk asked Zhi Men: What is the substance1 of Prajna (i.e. transcendental wisdom)?
門云。蚌含明月（光吞萬象。即且止。棒頭正眼事如何。曲不藏直。雪上加霜又一重）
Chih Men said, "A clam containing a bright moon." (Light swallows all things. )
僧云。如何是般若用（倒退三千里。要用作什麼）
The (asking) monk said, "What is the application2 of Prajna?"
門云。兔子懷胎（嶮。苦瓠連根苦。甜瓜徹帶甜。向光影中作活計。不出智門窠窟。若有箇出來。且道是般若體是般若用。且要土上加泥）。
Zhi Men said, "A pregnant rabbit."
1 - 體， means like a system or essence, a body (not in the sense of a human body).
2 - 用, function/use/application. Essence/body and function are complementary ideas that are used to analyze things. What comprises them, and what's their purpose? https://en.wikipedia.org/wiki/Essence-Function
For those of you who have read the foundational literature of the Buddha Mind School (AKA Zen Sect), you will know that Prajna is not any regular old kind of wisdom. Remember the 'transcendent' part?
A clam swallowing a moon has nothing to do with wisdom, and everything to do with Prajna.
Re-examine the Diamond Sutra, until it "clicks". People talking about it with vague metaphors isn't as quick as reading the textbook which explains it in plain language, without metaphor or symbolism.
By the way, Yuanwu annotates each of these sentences inline. The chinese I quoted it only the first 5-10 characters of each line. The parenthesized parts are the commentary explaining something about what's going on, but it's still just vague symbolism and not a clear explanation. It is a "hint" to the reader who still hasn't "got it".