Cast metals are rather brittle, normally? Good for complex shapes that may be further refined by machining, and in compression loads, but not in shear or tension. I would think they would shatter in a collision rather than bend like steel.
Model Y has been using casting for a few years now.
It's also among the safest cars in a crash: https://www.notateslaapp.com/news/956/tesla-model-y-receives...
In this particular test it was THE safest cars ever tested by Australian ANCAP.
https://www.thedrive.com/news/tesla-gigacasting-a-cars-entir...
Cast iron is already used in transmission cases etc, and it does indeed shatter. But it's not because its cast (although it can't be forged even a little; it breaks apart almost like sand), it's because it's actually just a name for an alloy. It's very high carbon (>1%) steel, which makes it very brittle but also very easy to cast. You can cast aluminum or low carbon steel and it will not be brittle at all, particularly if you let it cool slowly.
They claim that due to material advances and such, casting can meet or exceed the strength of typical 'forged' steel.