These are coursework essays for AQA English language and literature (we use Shakespeare as a cross-over piece)
The reason I did it like this was so I could comment on their work while it was still in progress rather than paper form - you do have to 'lock' the essays from your teacher 'tasks' page, to prevent coursework being done outside of school.
I'll definitely keep doing this for essays for all classes - I might even set KS3 some homework through this: It took me hardly anytime to write comments for each of the year 10's essays - more time for planning the next one!
I'm a yacapaca convert!