They were given "sign gifts" when the Gospel was still being preached to Israel, because the Jews had been taught by the prophets to looks for signs to signify that the Messiah was the Messiah.
Also, in Israel, signs justified a prophetic ministry.
John 2:18 Then answered the Jews and said unto him, What sign shewest thou unto us, seeing that thou doest these things?
1 Corinthians 1:22 For the Jews require a sign, and the Greeks seek after wisdom..
Once Paul was sent to the Gentiles and Israel rejected the Gospel, the sign gifts ceased.
If you will notice, after the books of Acts, it is a whole new world as far as supernatural acts by the apostles go.
And that is because the Greeks (or gentiles) were not seekings signs to prove anything as the Jews were.
Luk 17:6 And the Lord said, If ye had faith as a grain of mustard seed, ye might say unto this sycamine tree, Be thou plucked up by the root, and be thou planted in the sea; and it should obey you.
Miraculous works continued to be performed to this very day by living Saints, not for signs but for good. However, that is not what was being discussed.
Mat 16:18 And I say also unto thee, That thou art Peter, and upon this rock I will build my church; and the gates of hell shall not prevail against it.
Mat 16:19 And I will give unto thee the keys of the kingdom of heaven: and whatsoever thou shalt bind on earth shall be bound in heaven: and whatsoever thou shalt loose on earth shall be loosed in heaven.
Not a sign at all. An ETERNAL authority.