Unless your house is a modern bog standard estate one, do not let the deeds disappear. They may be of value when you come to sell. The Land Registry records (although very good) are not 100% accurate - nothing in this life is - so the deeds could be important to sort out any queries, quite apart from any historical interest.
If you let the bank have them, keep a photocopy yourself. If you have a solicitor, they may hold them free of charge (assuming they also have your will).