Gigi, thanks for the good thinking -- it's exactly the kind of question genealogists ask. In this case, there really was a Blizzard family, and there really was a Catherine who is mentioned in a Blizzard will, but when you read the will properly, you realize she was the wife of a business associate of Giles Blizzard who wrote the will, not the his daughter. So the Catherine Lewis in the will was not really a Blizzard at birth, but rather an Edelen. And she was never Mary Catherine; people in that era (1600s) rarely used multiple names like that.
One reason for keeping Mary Catherine Blyzzard as a fake profile (unlinked from all parents, spouses and children, so she doesn't appear in any family trees) is because she exists in just about every popular genealogy -- you'll find her in geni, ancestry.com, my heritage, etc beause so many people simply repeat things rather than doing research. Since she exists elsewhere, she is likely to be re-created on WikiTree by people copying form other sites. This way, when someone tries to create a new profile for Mary Catherine Blyzzard, WikiTree should tell them, "we already have one.
While the real Catherine Edelen married a real Thomas Lewis, there is also a fake Thomas Griffin Lewis with fake facts who is married to the fake Mary Catherine Blyzzard. Thomas Griffin Lewis will be getting a "disproven existence" notice for the same reason, in accordance with WikiTree policy.