So did people ever plant crabapples from seed? Of course they did. Just think of Johnny Appleseed. But those apples were normally used for jelly, applesauce, and cider and not for fresh eating. Even in Johnny Appleseed’s day, dessert apples were grafted.
There is one other caveat with using crabapples from a tree in the landscape. Make sure the tree hasn't been sprayed as an ornamental with a pesticide that isn't labeled for fruit tree apples. If it has, then the fruit should not be used. (Ward Upham)