It's just 4-4-2 with attacking wingers.
You wouldn't say that a team playing 4-4-2 was playing 2-6-2 just because they used attacking fullbacks, so I don't see why Conte's system is being called 4-2-4.
Although, 6-2-1-1 would be quite a good description of how Delneri had Juve playing when...