The book launch is a "ceremony", an "event", to make official that the book is out. They could just take the book out of a van and put it in a shelf, but then nobody would notice "something is happening". So yes, I think it is embedded in the event, if you're promoting a book for people to notice it, you would be a bad promoter if, after people notice it, you didn't give them access to it.
That said, I don't think your question was silly. There are many ways of doing things in this vast world of ours, and if I was in charge of that book promotion, I would just be flattered by your interest and happy of being of service :)