EVs typically have a different motor for the front and back wheels, so they would have most of the same traction benefit of a 4x4 system. In the case of companies like Tesla, I think they market as AWD because that implies a system designed for slippery roads, and not off road trails. 4x4 or 4WD can differ a lot but all typically include a locking center differential so that even if both front (or rear) wheels have no traction, the vehicle can move.