The Protestant Hymnal has been a very effective conduit for the introduction of heresy, because concepts set to music enter the mind through channels not normally subject to critical inspection. Error in a sermon or an essay is much easier to detect that is error in the lyrics of a song.
The typical hymn-writer is long on emotion and short on his understanding of the Scripture. Many of the lyrics of hymns are nonsensical and illogical; many contradict the Scripture; some even are blasphemous.
In the book of Psalms, the Lord God has provided for his people a body of lyrics which, being Scripture, are pure and edifying. Those are the lyrics which ought be set to music and sung.
The phrase "psalms and hymns and spiritual odes" makes better sense if the Greek conjunction KAI is rendered "even" instead of "and," so that the verses in question read "psalms, EVEN hymns, EVEN spiritual odes". The Apostle is viewing the same entities -- the Psalms (which is to say, the songs) found in the Book of Psalms -- from three vantage points.