On my laptop, I see the same thing as you when using a full-size browser window, from the desktop site
https://buytickets.eastmidlandsrailway.co.uk/ , but if I reduce the browser window size by half before making the journey search then I instead get the mobile site
https://m.buytickets.eastmidlandsrailway.co.uk/ which does not offer the paper ticket option (see attached screenshot). Similarly, on my mobile phone I get the mobile site by default, but if I go into the Chrome browser settings and tick "desktop site" before making the search then I get the desktop site with the option of a paper ticket. The EMR mobile app looks similar to the mobile site and does not offer the paper ticket either.