mrz,
I'm being dumb here, and we're clearly talking at cross purposes to some extent. Perhaps if I just said how I've seen them work, and how I've seen them not work, it might be helpful.
One teacher at my school gives students wordless books initially (in the first week). She thinks the pressure of not having a 'right' story makes it easier to detect students who are unfamiliar with books, and to gain some sense of the broader skills they have which are relevant to reading. I think there's merit in this, that it does really help to identify kids who find that exercise incredibly dull because they know that words give meaning from those who don't. It doesn't affect how she then teaches SP, but it does affect how she asks TAs, reading support staff and parents to help over the first term (which may not be by giving 'wordless' books but by asking parents to read etc.) This seems sensible to me, tailoring an approach to some learners in their one-on-one time.
The vast majority of what I do with the vast majority of students at reception focuses on 'decoding', on reading books which have pictures, but where my aim is to get them to see, using phonics, how graphemes combine to form words. These students are not 'bizarre', they get meaning through the normal processes of decoding. As far as I teach 'comprehension' it is merely to assess if they have understood, and to use the fact that as an unpaid member of staff I have time to reinforce messages about reading being useful-to have a brief chat (insofar as you can with a 4 year old) about their pets if they've read a book on pets, for example. They will probably never see a wordless book again. I'm not advocating their general use for all readers for an extended period of time.
But, even in reception, there are some students where all three teachers 'revert' to wordless books for some of the time. Some of these students have particular difficulties in even understanding what a book is, and removing the pressure of getting it 'right' for a short time seems to help. Others, towards the end of reception year, seem to present anomalies in, for instance, being able to sound and form words but it all falling to pieces in a book, or having developed skills in story telling and understanding but not showing these at all in response to books, with corresponding demotivation. Some SN kids were simply so tired by the end of the day that, once in a while, it is felt that the effort of 'decoding' would be too much and that work on other reading skills would be a good use of time (this happens less now, the scheduling's better). For all these kids, despite my initial shock and worry, moving to reading just one or two 'wordless' books (the longest ever with one child was four weeks-during which time he continued to take part in class phonics activities) really seemed to have helped. And in some cases I'm asked to use them simply to see if resistance to reading is about the difficulty of decoding or something else. I think they have a real role to play there, I have in essence been 'converted' to their use, and think they are more effective then the mixed messages which would be involved in using a book with words but not demanding decoding.
What I fear in discussing their 'use' in reception, in advocating ditching them because they're expensive, is that you end up with a system tailored for 'normal' learners-for those who don't have any difficulties, and up either not resourcing or stigmatising as 'less good' pupils who have specific needs and who really do seem to be helped, both diagnostically and in developing accuracy, by these books, and failing to recognise that all readers also have those needs. I really do think they have a role to play, they may seem daft to 'normal' learners like the OP's daughter, but they're really, really not-they can do certain things very well (better than a quality story book)>.