Vehicle question - the value of heavy duty frame on inner squared, and heavy duty roofs


Given the weight of a heavy duty frame and the heavy duty roof, is there any point in having them on the inner tiles of a vehicle? and since roof tiles don’t need to be placed on the same tile of a board or quarterpanel, why bother with heavy rioofs at all?

The heavy duty frames on the inside are good for explosions or you know getting shot at by a chicken walker and not having your frames get destroyed.

If I’m not mistaken impacts will propagate through your vehicle a bit. Which means if you hit something hard, your exterior heavy duty frames will bounce off, then your internal light frames will shatter. Not sure how that applies to roofing though.