Vector instructions are certainly usable for scalar computation, although it doesn't make much sense --- you basically just use one piece of one vector and throw away all the other results.
Fibonacci is a toy example but illustrates where the vector instructions do become useful: if you want to compute the n'th term of various Fibonacci-like sequences with different starting conditions but the same recurrence, then you could do them in parallel using those instructions.
Fibonacci is a toy example but illustrates where the vector instructions do become useful: if you want to compute the n'th term of various Fibonacci-like sequences with different starting conditions but the same recurrence, then you could do them in parallel using those instructions.