Earlier quoted context omitted.
Don't they have the same protections? I think it's perfectly fine to download an ebook and mail somebody your harddrive for them to read it no? I'm not sure it's legal for you to photocopy a physical book and mail them those photocopies even if you burn your book.
You typically can't just mail a hard drive: you have to share access to the account that was used to purchase the ebook.
Rather than mailing your friend a hard drive, you could mail them a door key and they can come over and use your computer to read the ebook or your couch to read the book.