Thanks for your feedback Cardibach. I think sometimes it's easy to get confused between what's best for the population as a whole, and what's best for your child - What you're saying is to focus on the population as a whole, which makes sense from a teachers point of view.
For my child (who reads for at least an hour every night, discusses all his books with me, and is encouraged by me to read more challenging books, whilst being allowed to read whatever he wants) it's not a useful thing - especially as he has inherited my love of reading in bed, and hatred of trying to read in a room with people whispering and giggling, in a hard chair!
But, as I say, it's clear that this is one of those times where the right thing to do is to acknowledge that schools can't make individual decisions based on the individual child, and that for the school population as a whole it is positive (if done correctly, which I'm not sure it is in DS1's school, but that's another issue maybe!)
Although, I'm interested in the giving reading for pleasure status thing - for me, reading is fun and relaxing, and school is for work. By coding reading as a thing you have to do at work, are you reducing the reading is a pleasure thing?