Yes our fruits are a witness of the Spirits work. But signs following is a large part of the Christian faith. Just read the gospels. Yeshua is healing or casting out demons as often as he is doing anything else.
And how about scriptures like these?
21: He that hath my commandments, and keepeth them, he it is that loveth me: and he that loveth me shall be loved of my Father, and I will love him, and will manifest myself to him.
John 14:21
22: And whatsoever we ask, we receive of him, because we keep his commandments, and do those things that are pleasing in his sight.
1 John 3:22
Not to mention
THIS:
17: And these signs shall follow them that believe; In my name shall they cast out devils; they shall speak with new tongues;
18: They shall take up serpents; and if they drink any deadly thing, it shall not hurt them; they shall lay hands on the sick, and they shall recover.
Mark:16:17-18
Fruit bearing and signs following are the full expression of the Christian. Not one apart from the other.