But looking at the comparison, do you really find GNU Parallel that much harder to understand?

  parallel sh -c "echo hi; sleep 2; echo bye" -- 1 2 3

    parallel echo hi";" sleep 2";" echo bye ::: 1 2 3

  parallel -j 3 ufraw -o processed -- *.NEF

    parallel -j 3 ufraw -o processed ::: *.NEF

  parallel -j 3 -- ls df "echo hi"

    parallel -j 3 ::: ls df "echo hi"

And if you are looking for the single page overview, why not link to the cheat sheet: https://www.gnu.org/software/parallel/parallel_cheat.pdf