California’s wine grapes (vitis vinifera) aren’t suitable for eating. Some varieties (vitis labrusca) can be used for table grapes or wine grapes, but those aren’t really grown in California.
Did I just get lucky? Anyone else do this?
Vinifera makes a perfectly fine table grape and grape juice, depending on the varietal.
For example, Thompson Seedless, an incredibly common table grape, is vinifera.