Should I write an inscription in my gift book?

I know this question has been discussed on here, and I've read through some archives. It seems book lovers offer conflicting opinions. So I'm asking in case anything has changed in the new mostly digital reading age. I am giving a book to my son who has "big news" he's been saving to tell me in person when I see him in a few days. I suspect he's getting married or moving away. It's a new hardcover, of an old book. Nothing special about this copy. I just want him to have it. It's special to both of us becaus