Full disclosure, I'm totally new to surround sound and Atmos, I do this professionally in stereo...

I've downloaded the Dolby software and render thing, got everything working in ProTools and have been messing around on headphones having some fun in Atmos and just learning. My biggest hurdle in all of this is trying to figure out how to send an Atmos mix to a client to check on headphones.
It seems like a huge issue, even if you give them an mp4 out of the renderer they still need something like the Apple earbuds with the decoder built in. So, why can't I just play the Atmos file back on the renderer and then record my headphone feed in stereo and send that to a client? Shouldn't that solve all my problems, and they can listen on any headphones without anything special to get an idea of translation on Apple Music or something?
Am I missing something? This seems like a super simply solution. Going even further, what's to stop me from just uploading that dolby render anywhere, even on a YouTube video (where Atmos isn't supported)? This just seems way too easy...