frame question

I do have a frame related question. Standart Langstroth frames have a bulge on the sides toward the top, which allows the frames to touch each other towards the top but not at the bottom. This allows bees to move from one frame to another easily. Now I want to build my own frames but I do not want to deal with making this bulge toward the top. I thought that instead I can make the top bars wider than the side bars. This way the top of the frames will touch each other but there will be gaps between the sides. Do you foresee any problem with this design? Is there any reason for some of the top portion of the side bars of a frame to touch each other?

Thanks for any clarifications. I can share a drawing if my question is not clear.

A suggestion is to amend the title to Bee frame......
I wonder if the frames have that bulge because prior to the inclusion of the bulge the bees built
anyhow causing the frames to swing and stick or jamb together?