The police can be used to help all kinds of good purposes.
"God has sent you among us for some good purpose."
It would serve no good purpose, he knew, to attack her.
Now she realized that getting lost had served a good purpose.
But neither will we throw our lives away to no good purpose.
"It wouldn't serve any good purpose for you to see her now."
I mean, it obviously is meant for a good purpose.
I see no good purpose to be served by our remaining.
Just as you never ask whether people are going to use your knowledge for a good purpose or a bad.
So it has served a good purpose in many ways, too.