Ah I see. The "connected" and mitred flanges like LianLi uses them actually require a very specific press die, so you need custom made tooling for that. I asked
@dondan about this when the A4 had the front flanges showing like the Compact splash does.
Yes, it allows to use a little bit thinner material, but overall the normal rigidity benefit from flanges compared to no flanges is much higher than from these special flanges to regular flanges.
For LianLi, this special flange is important only for aesthetic reasons. As they save weight, money and production time by making the frame and shell the same part, similarly to the Comapact Splash, strain relief gaps would show on the front and top without this special technique.