Actually, I am not trying to convert anyone. That is the role of the Holy Spirit. But, I do know more than you think but I will ask the obvious question - WHAT do YOU believe about "holy water"? In YOUR words.
I believe that it is water that was blessed by a priest (I’m sure you know how we think of priests) asking that those who use it be blessed. Sacramenatals, and we have a lot of them, remind us of the Sacraments and our relationship with Holy Trinity. When I make the Sign of the Cross, I am blessing myself, I am making God’s Grace present to myself and I am worshipping Him by using the gifts that He gave us.
I personally use Holy Water to bless our fields and our house. I am imploring God’s help through the use of a physical reminder and presence of God’s Grace.
Expecting to be healed of something by using Holy Water isn’t acceptable to me but God choosing the Holy Water to heal is a glorious occurence. God works throughout creation and uses who and what He will to further His Kingdom, if it is God’s Will it will be done with or without the use of sacramentals.
IOW, sacramentals remind us of God’s Grace and make His Grace present to us in a real way.
The sacraments, OTOH, are true encounters with Jesus, they also impart Grace but in the most intimate encounters with Our Lord and Savior Jesus Christ.