The more cards you display, the stronger your message. Six Pass cards shows a Yarborough. Some players prefer to indicate emphasis by the way they put their bidding card on the table. Slamming means this is the final decision for the partnership. Floating a bidding card indicates resignation.
Bidding boxes are a wonderful thing.
You do not need to pay attention all the time because you can review without asking for a review. You do not need to worry that other tables will hear your auction. You do not have to worry about what someone bid, did they bid two notrump or was it three notrump. I think if you try them, you will like them. All functions in our Unit require the use of bidding boxes, unless you have a disability that will not allow their use.