It is not arcane, you just have to read docs, like for every command line tool. Different cli applications have different syntaxes usually influenced by their domains, eg compare find, tcpdump, iptables, cut, docker.
The tool is originally meant to do various conversions of formats of data on 8-track tapes and both its name and syntax is reference to (arguably less bizarre) syntax used by IBM's JCL to produce contents of tapes that need that kind of conversion to be usable on unix.
I used dd a lot to burn images on USB. And that command is simple as expected.
I didn't say it wasn't simple. But it is very weird.
Do you realize that anyone can make a cli tool with whatever syntax they like? :) Also, see "man xm", which uses quite similar approach. And there are probably many other examples.