True, you could use the double nutting or Allens wrench, but going back a few posts, the big advantage to a stud, especially in an aluminum block, is that you're not always grinding on the threads rotationally in the block every time you take the head off. All the threads in the block are engaged, the pull is straight, rather than straight AND rotational, and the friction and drawing forces are handled with the hardened steel nut.
I hate helicoils . . .