This is what made the “ln” argument order click for me as well.

Another piece of this parallel is that (with cp and mv) you can omit naming the destination file - you often just name the directory:

  cp /other/dir/foo.txt .

The corresponding shortcut with ln is not naming the destination at all, and the symlink is created in the working directory:

  ln -s /other/dir/foo.txt

Both of the above are my most common usage patterns, and the abbreviation of the second argument in both helps reinforce the parallel between cp, mv and ln.