It's not a complete innovation. Voting on paper has been the practice for some divisions for some time (deferred divisions where instead of voting immediately, MPs vote on paper the next day).
Quaint maybe but I would not go so far as to say absurd. There is something to be said for physically getting up and indicating your choice that way. Seems to me to give more weight to the process. Pushing a button seems rather clinical by contrast. Plus I am sure they appreciate the piss break.
