Yes, there are relays to connect the clients together and then the transfer is direct.

Several years ago when I was doing consulting I had lots of clients that blocked all the normal file sharing domains to prevent people from getting files into servers but magic wormhole always worked for me. I’d stash a wormhole-william (magic wormhole compatible Go application) executable in our installer deliverable and then I could update the software without IT’s help in the future (I often had RDP access). The headaches saved by cutting red tape were worth the risk for me.

Maybe I’m just old, but I traveled by plane recently (I don’t fly very often) and seeing everyone around me mindlessly scrolling short-form video content was shocking. Looked identical to the people in the space ship in WALL-E.