Hummm.... sounds interesting....
They can be if they are made properly. Unfortunately there are also cheap and nasty ones with about six raisins and a bit of syrup in them. As I say the missus makes her own to Delia's recipe https://www.deliaonline.com/recipes/books/delias-happy-christmas/home-made-christmas-mincemeat . Though she uses vegetarian suet, not always easy to find.