I think there are good and bad points, and which will out depends a great deal on what is in the books, and a great deal on individual teachers. If the selection in the books is all from stuff that's easily or cheaply available, it'll be very annoying, BUT they could potentially be a godsend, and they do look to be very affordable. As Andante points out, having got a student to spend £20 or more on 3 books for an exam, it's difficult to then say "oh, and now get this too": but if a student can buy a book for grade 1 that's £6, or £10 (and that's cheaper than many of the albums available) then even a selection off the alternates list to go along with the book won't break the bank.
Just for a specific example, June In Paris on the current G3 list sounds really pretty, but unless a student was dying to buy it I'd feel a little bashful asking a parent to spend almost a tenner if they'd already got, for example, 50 for flute for the study and one of the Baroque albums for list A, just to pick at random... they've already spent £13... and neither of those is a particularly expensive book, and both reasonably good value in terms of the amount of music you get. (When it comes to French publications and buying one sheet of music for a tenner

) If however, the child has a book which covers two lists for which they have paid £6.50, or potentially just £3.25 if the teacher already has a piano part they're willing to loan, then £9.95 suddenly looks a lot more affordable - or a new non-syllabus book after the exam that will really bring the student along... and so on and so forth..
Yes, I'd prefer to buy a whole work, wouldn't we all, but it isn't always possible.
I think, as with anything, it depends partly on the person using it. Yes, for some teachers, it means they will effectively ignore half the syllabus, and it could probably lead to more of the parent buying the next book as soon as the child has finished one exam, etc etc ad infinitum. But that happens anyway, and plenty of teachers are very unimaginative when it comes to the syllabus anyway. (My just-passed-grade-3 student was inherited from a teacher who clearly was getting her to work on pieces that the teacher knew and liked, despite my student really loathing one of them and not liking another, without even making very imaginative use of the music said student already owned

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Sure, there are drawbacks... but there are potential benefits too. Which side wins out surely depends more on individual teachers than on the publications themselves. Here's hoping that the AB have also done us proud by sourcing some of the more expensive or difficult-to-find pieces in the exam books *all digits crossed* and we won't find they're full of things that are readily available and which students are going to end up buying eventually anyway or already own from previous exams

I'm deeply ambivalent about the prospect, but I'm willing to hope that it will be a good source of affordable music at the right level for prospective candidates, and a good starting point (I devoutly hope) if not necessarily the be all and end all of exam music.
(if the books turn out to be full of studies from the 76, and pieces available in good value albums that I'd be asking someone to get anyway or buying myself anyway - then I shall be disappointed! But it is going to happen, so we're better off trying to work out how to make it work than moaning about it!

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