Year 6 English self marked homework

[user1496859259]

Hi my son who is in year 6, ( last year of primary) came home from school last night and said, that he had been told to mark his own homework. The homework was to write 8 sentences of your choice and each sentence had to include a word from his spelling list. And also to write a list of suffixes. I asked him "how do you know these are right" his response was "i asked the teacher if the list was correct" and she said "I don't know". When I spoke to the head teacher she replied "speak to his class teacher, but there is evidence out there that proves that children who self mark work understand where they have gone wrong and grow from this".
I would like to hear other people's opinions on this as im really baffled to there way of learning.
Thanks

List of suffix, I think he can look it up himself, but sentences he wrote, I don't know if self marking works. I think my dc did peer marking, children swap their work and check out each other's works. I think self marking works for subject like maths, when they have only one correct answer, and checking out where he made mistakes help the child understand better. But no, I don't agree with self marking his own sentences he wrote. I will be baffled too.

Marking his own homework? Then what teacher does? Strange concept.