Ints and floats are represented differently and so, if we want to put an integer array into floating point registers, we need to have casts. If you were to simply call SetFloatArray, you would get nonsense values in the floating point registers.
Even using casts will fall foul of the C aliasing rules - which mean that the compiler can assume that a read of type will not be modified by a write to a different type so can be reorderd (unless one of the types is 'char').
Not only that, but there are systems that will fault is an invalid FP bit pattern is loaded into an FP register.
David