When we add links to notes, a contradiction is even more valuable then supporting or add-ons. A contradiction will naturally make you think and have a conclusion of these contradicting facts.
It also eliminates confirmation bias somewhat, as it will remove the echo chamber from your slip-box.
They naturally further the conversation between your notes.
Reference
Ahrens, Sönke. How to Take Smart Notes: One Simple Technique to Boost Writing, Learning and Thinking. 2nd edition, Revised and Expanded edition, Sönke Ahrens, 2022.