As far as I can tell, right now it's only a statement that Central Government intend to change national planning policy - we'll probably see the change officially in April. Councils, as ever are free to implement local policy differently as the NPPF is sort of a reference document rather than rules that councils must simply repeat - it does, however, give a clear statement that central government don't approve of the notion of treating all developers like cash cows to be milked as they see it as stymying the growth of self building. Councils know that they really need to toe the line on major issues that find their way into the NPPF, particularly seeing as there is performance monitoring related to applications they turn down (and they would, if you didn't agree a 106 with them) that are subsequently passed after appeal (which is far more likely to succeed if your appeal relates to issues where the NPPF would have assessed the application positively)
I'm glad it's going away; councils have had an easy ride, taking money off self builders, claiming that they will use it to help other people afford a house (a sort of double blow, really, as one of the prime motivations for self building is to make your house easier to afford; not only do you have to afford it for yourself, but you formerly also had to help some other lazy **** [who could just as easily afforded their house by self building] onto the ladder), and translate that into actually embracing the notion that people should be helped to self build as a way of affording a home - councils are under mounting pressure to make available the necessary resources and assistance to do so, rather than simply being required to remove the financial barriers they threw up
I'm not certain I agree that all sites under 10 units should be exempt from S106, but that's a pretty big stick in itself to get a council to pull its finger out and implement CIL instead (so that only self builders get relief for that) so for those councils who were formerly incentivised not to update to implementing CIL and instead stick with 106 (i.e. do nothing, so they could carry on charging everyone for various contributions) they are now placed in a "if you continue to do nothing then all those developers who submit sub-10-unit sites can build them without making significant contributions to your coffers" situation
I won't even start on those councils who've taken a lot of S106 money for affordable reasons, yet aren't actively building any affordable housing - that's outright fraud and good for central government putting an end to it