Some see the greeting as the standard way Paul starts writing his letters. If it is just a standard way Paul writes his letters, did Paul give any particular value to his greetings? A negative response fails to take into consideration the following.
The first readers of this letter to the Colossians did not have the privilege that we do: they were not able to read all the letters of Paul. They would not know that this is Paul’s standard procedure of writing his letters. So let us read this letter as the Colossians read it. To them, it is the first time they have received a letter from Paul so these words had real meaning and impact, and we should understand this as we read this letter. The second letter they may read from Paul is the letter they were to receive from the church in Laodicea (see Colossians 4:16). Besides that, we do not know if they read any other letter from Paul.
We should also take into consideration that Paul did not write his salutation here in the same way as in other letters. There are differences in sentence structure and choice of words. This means Paul put a lot of thinking into the words he used in his greeting to address each church.
1 Paul, an apostle of Christ Jesus by the will of God, and Timothy our brother,