A key distinguishing factor is that iroh is meant to be used as a library that you can embed into your desktop, mobile or embedded apps.

Up to now our users are mostly teams that have a rust or C/C++ core, such as https://delta.chat/ . But now that we have bindings teams who use other languages should be able to use iroh.

So you can write e.g. an android and ios app that uses iroh direct connections under the hood, and the app user does not have to know or care about this at all.