Stupid school end of term. What's the deal????

DD in yr9 in again hassling me to end her school year NOW. All reports have been written, everything marked - no more work to be done, so what's the point in her going??

The school has sent some info, saying classes continue as normal this week, then "In School Activities" for the last week. It all sounds like bollocks - why does the school year end 2 weeks before end of term iykwim?
I'd rather she go - the school has bothered to send a letter saying they all should go, but I have no leg to stand on when they are doing nothing of value.

What happens at your house and why do they do this????????