Aside from catering from those with extreme anxiety and parnoia around lost words, we built exporting so that you can move your words if and whenever you may want to, to make paranoid backups for yours, to share with your nan, to send to your publisher or to wallpaper your room with. All valid reasons to export your novel. You can currently export to .docx, .odt and .pdf. Of course let us know what other formats you may want in the comments.
Read the release blog on exporting your novel.