For Team Conversations, rather than scrolling all the way to the bottom of the page to find the email address, there is a “Start a Conversation via Email” button at the top:
It would be great to have that same button available for Project Conversations, just so you don’t have to scroll all the way to the bottom on those pages either.
(I do know that the email address is automatically projectname@mail.asana.com but sometimes it’s nice to copy-paste to avoid potential typos.)