You are tasked with writing a binary tree, and you pick car and cdr ... A key-value tuple-space... Complex numbers...
The point is they are 'wrong' in every context. For LISt Processing, they should probably default to something to do with lists.
And caaar et al are a fine example of why I completely skipped common lisp in favour of newer lisp-likes. Perhaps it happens to all languages eventually, people add a convenience here, an shortcut there, and a doodad here, and before long you have an impenetrable thicket.
And these things seem convenient, but they are a huge extra cognitive load, and impose a further learning cost even to practicing experts who have to keep up with the latest doodads.