Update: Er. Whoops!
No. Without the last statement, the loop would iterate twice more ('cat' & 'dog') than it needs to. For such a small dataset as shown, the difference is minimal, but if the dataset were large, and the key found early, then a significant saving results by short circuiting the loop.
Examine what is said, not who speaks.
1) When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong.
2) The only way of discovering the limits of the possible is to venture a little way past them into the impossible
3) Any sufficiently advanced technology is indistinguishable from magic.
Arthur C. Clarke.