I like writing in Paper so much that I use it to write things I'm not going to share via Paper. I actual copy and paste out of Paper into email or Google Docs when I work for companies that don't use Paper. I'll write things like READMEs in Paper first, before moving them to a .md file.
The UX is so well thought out. For example, the link creation is so simple. You copy a URL, like from the URL bar, then highlight the text in Paper that you want to be a link, and Cmd+V. The highlighted text will now be hyperlink to the URL on the clipboard.
The mobile app is handy too.