You cannot teach the main purpose of the Baptism of the Holy Ghost is to overcome sin if God gives the Holy Ghost to them that obey Him (Acts 5:32) and be consistent with scripture.
Sin is disobeying God (John 14:15, 1 John 3:4) and Jesus is the Savior of those who obey Him (Hebrews 5:9).
Someone who is sinning is disobeying God and is therefore not saved and not a candidate for the Baptism of the Holy Ghost.
The grace that saves (Ephesians 2:8-9) teaches the saved person to deny ungodliness and worldly lusts and live soberly, righteously and godly in this present world (Titus 2:11-12, Galatians 1:4) and have dominion over sin (Romans 6:14).
This is an obedient life that qualifies the saved person obeying God to ask and receive the Baptism in the Holy Ghost (Acts 5:32, Luke 11:13).
Even Jesus Christ as our ultimate example always perfectly obeyed the Father before He was Baptized in the Holy Ghost and when the Father did so He commended the Son as pleasing the Father (Matthew 3:16-17, Matthew 12:18, John 8:29).
I do not deny the Baptism in the Holy Ghost brings a fuller revelation of Jesus Christ and the scriptures and helps us to walk more intimately with the Savior and thereby makes it easier to live victoriously and overcome sin.
We can also have a greater and more effective prayer life which also enables us to live on a much higher plane of victory (Jude 20, Romans 8:26-27).
However faith is Jesus as Savior from sin is what gives victory over sin (Matthew 1:21, Acts 3:26, John 1:29, 1 John 3:5, Galatians 1:4, Titus 2:14, 1 John 5:4, Romans 3:31) and the grace to obey the commandments of Jesus Christ.
By grace and faith in Jesus Christ we can have victory over sin in our own life.
The Baptism in the Holy Ghost after salvation to those who obey, ask and please God is primarily for the purpose of having an impact on those we witness and preach to (Acts 1:8, Luke 24:49).
To preach repentance and remission of sins (Luke 24:47), to break the bondage of the devil from them (Luke 4:18, 2 Corinthians 4:4) and penetrate their hearts with the truth of God (Acts 26:18, Hebrews 4:12).