Why do CCEA exam papers have boxes on the back for question marks

If exam papers are now scanned and marked electronically by examiners then why do CCEA still print boxes on the back pages of their papers that say "for examiner's use only" and have the question numbers then spaces for the marks to be written for a particular question in beside that question number.

I was just sitting in the exam hall once and after I had written my centre number and candidate number on the front and waiting for the exam to officially start I just turned one of my papers over and noticed that on the back