I have seen wadjan but I did not know the name, the one I have is sorta a cross between the two. No flat bottom inside the pan but it has handles like the wadjan (probably due to the weight).
Yeah, it isnt quite like a carbon steel wok but most people in North America wont have a a wok burner to hold the round bottom so they need the flat part.
You also definitely cant cook in them quite like a wok since as you say the cast iron holds so much heat. I usually just get it real hot on the burner for 5 or 6 minutes and then stir fry something. You have to take the food out when it is ready though because moving so much iron off the burner doesn't cool it down as quick.
Here is a link that might be more useful
https://i.imgur.com/NKXQpXZ.jpeg
https://i.imgur.com/4MlLayk.jpeg
Yeah, it isnt quite like a carbon steel wok but most people in North America wont have a a wok burner to hold the round bottom so they need the flat part.
You also definitely cant cook in them quite like a wok since as you say the cast iron holds so much heat. I usually just get it real hot on the burner for 5 or 6 minutes and then stir fry something. You have to take the food out when it is ready though because moving so much iron off the burner doesn't cool it down as quick.