I think this comes down to wording, which is important and makes or breaks a question on any site in the StackExchange.
If the question were "How do I properly laminate with contact paper without leaving bubbles?" This would be on topic.
As it stands, the question specifically is asking how to put a cover on a book. This is not an art project. This is not a craft project. This is a book preservation project, just because they happen to use materials that are often used in craft projects does not make this a craft related question.
I would submit that this question is off topic, and any future questions that are not craft related but happen to use crafting supplies would be as well.
Example of proposed off-topic questions
- How do I make yarn strong enough to hold up a bird feeder?
- What sewing needles are best for emergency stitches?
- What kind of fabric is best for filtering cheese curds?