I chose not to copy the features of magic wormhole because it seemed to me (at the time) to be very complicated and lacking in features crucial to myself (namely restarting transfers [1], sending folders without zipping them).
This has been to my benefit, I think, because I can iterate on croc quickly without having to conform to the wormhole spec and I've since added features still not available in wormhole (like restarting transfers [1], and ipv6 support [2]).
That being said, I really like magic wormhole and consider it my inspiration. And I'm glad that you ported it to Go!