The "casting" advantage basically just hides bugs. Because it's often not okay to access just 16 or 8 bits of a 32 bit number; the value is being truncated and that could be a bug.

However, when the number's range is small enough, such code appears to work. Finding the bug is delayed until larger values occur, which is not until its deployed in the field or someone thinks of writing better test cases.

Anyway, if it is okay to truncate, the right thing to do (and ISO C conforming) is to access the underlying type as that type, and then cast the result, not to cast the pointer. I.e. rather than:

    int x = *(int *) ptr64; // breaks on BE; not kosher with ISO C aliasing rules

this:

    int x = (int) *ptr64;  // works on LE and BE

We don't even need the casting operator in the second example. So it's less syntax and clearer code to do the more portable thing.

If we want the bits for that int from some other part of the wider word, we can use shifting and masking.