Our workshop came up with the following reasons - I have tried to group them sensibly, but hey, it's Friday!

Internet issues:

• not always reliable
• many students do not have access from home

learning support

• aids a variety of learning styles
• children learn to browse and share - easier to share a book than a screen
• multiple references
• fact-checking
• note-taking
• central area

Cost factors - may be cheaper to maintain than ebooks and readers

Books are good to hold, physical aspect

Collection is a large visible presence, reminds users that there is variety available

If you have a collection, you need a librarian!