A closer look
When you are driving through an active hostile zone, traditional boxy vehicle design is completely lethal. Sloped armor is a brilliant geometrical trick employed by heavy infantry carriers. By aggressively angling the thick steel sides inward instead of standing them vertically, incoming projectiles are far more likely to violently deflect off the surface rather than digging in. Furthermore, the angle drastically increases the effective thickness of the metal the projectile has to penetrate. It is physics actively working to aggressively ruin someone else's day.
