I think they meant that function parameters are vectors when defining a function:

  (defn foo [arg1 arg2 & rest] ...)

As for data-structure literals, it's nice to be able to write

  [1 2 3] vs (vec '(1 2 3))

  {:key1 "val1", :key2 "val2"} vs (hash-map :key1 "val1" :key2 "val2")

Agreed, all pretty minor points, but all nice to have. Function arguments are easily distinguishable and creating maps/vectors is simplified.