This is more from the perspective of the language designer, not from a "you get a binary, is it malware" one, in which case Turing-completeness basically has no importance. So for an example...

Many exploits use stackoverflows to get the execution of arbitrary code. You can prove that in some bounded languages such things cannot happen, regardless of the inputs the program gets.

Obviously you still rely on assumptions such as "the OS is not going to do random things with the memory", but that's outside of your power anyway.