Even if she were sinless what difference does it make?
Salvation...
What does Christ prescribe for our Salvation?
He prescribes our obedience that we recover from the disobedience of Adam... Matt 28:20
He prescribes purity of heart, which is why He sent John as His Forerunner so as to prepare His Way in the human soul, preaching the baptism of repentance in preparation for the coming of Christ which is at hand...
The Blessed Virgin is the original sinless one among those fallen in Adam, and was so to the degree that she conceived Christ God into flesh in her womb...
THAT level of purity is far beyond anything we can imagine...
She is the TYPOS of purity for the birth of Christ IN us...
And she is the TYPOS of the Church that births us in Baptism into Christ...
As we are Brethren in Christ with Christ, she is our Mother as well, who gave us Life in her Waters of Regeneration...
Christ is first-born from the dead that He should have many Brethren...
His Brethren, you see, have Her now as their Mother too...
For as God is our Father, so is His Mother our Mother, the Ekklesia...
Her purity set the standard for entry into Christ in Baptism...
For as many as have been Baptized into Christ have put on Christ...
The purity of the Mother of our Lord is the Gold Standard of purity for Life in Christ...
And THAT, my Brother, is the difference it makes...
Arsenios