This was the second miraculous sign that Jesus performed, having come from Judea to Galilee.
Other 'signs' in John's gospel are not enumerated, so is there some reason for linking this 'sign' to the water into wine? There obviously is and these chapters 2-4 do form a coherent section of the Gospel. We first have the picture of the dead (or nearly dead) coming into life, then the teaching to Nicodemus of the new birth, then the spelling out to the Samaritan woman of the Spirit's invigorating and now the actual raising up of the dying son to life.
In both instances it was the command of Jesus that worked the miracle; in this instance it took place 16 miles away in Capernaum. Faith comes from hearing, not from seeing.