I empathise with what you say Terry in terms of the family history thing being fun and a learning experience. However, all too often these companies that you speak of offer the service that you describe are providing you with either spurious arms that were never issued, or with the arms of someone who happened to share your surname, who were, nonetheless, not actually realted to you.
These are all reasons why adopting them as a family crest is an historical nonsense. That said, they can look nice on the hallway wall, so if that is what floats your boat, go for it!