I think since there is angle to the blades, it will still contain and make a berm, but the flat blades would be less likely to build up with soil and easier to clean off if they do.

 I have flat rippled blades on my BB units. I am not entering the soil with them, but they are set really close to contain the shank blow out. Here is a video that you can see them work a bit. This was wet soil, and 2 units did plug, but I widened the spacing out an inch and they quit plugging from then on. I am on 15" spacings, so the berm disks are quite close. I was having more issues with mud building on the front blades with the depth bands.