As a cautionary measure, I had not planned on submitting DNA. I have read many varying statements/articles on the privacy laws. Not planning on committing a crime !

However, I have hit some really big road blocks in my Italian search that I have not found a way around, and am considering submitting my DNA for testing. I've read some of the helpful posts here, and from what I've read, I'm not sure it would even be helpful to me.
I have been on Ancestry for 8 yrs. I regularly check for other members looking for my same ancestors, and there has never been one, ever. So, I'm not sure it would have any beneficial results for me. Wouldn't it be safe to assume, that if someone had tested their DNA with Ancestry, and was in their database, they would also be a member with a tree? I have doubts my Italian relatives would be in any database, as I can't even find a shared one on Ancestry, Family Search etc.
Additionally, both of my GGP's, who married in NYC in 1905, state where they are from in Italy on the marriage record, but neither of their baptism records have found at the local parishes. Based on their parents names they gave, we think we found their families in those communes, and can trace the families back to the 1700's. We cant be 100% certain with out a baptism record each of my GGP's, but we think they have a long history in those communes. They are from Lombardy and Piedmont in northwest Italy.
We believe both families relocated (separate regions). And haven't been able to determine where they went as of yet. Eventually both of my GGP's separately immigrated to the US somewhere between 1895 - 1905, and met in NY.
Based on this information, even though we can't find my GGP's baptism records to verify his birth/parents, the families we believe are theirs, come from the northwest region for many generations. And I don't believe it would help me identify where they disappeared to after my GGP's births, and until they came to the US. My grandmother, their first born in NY, never spoke of cousins or any relatives of her parents in the states. My mother, aunts and uncles never met any, so it doesn't seem like any other relatives were in the states, or so it seems. I guess there could be a small possibility. Lastly, it is doubtful that my Italian relatives in Italy are looking for their American relatives in the States, from ancestors that immigrated there long ago.
While learning more detail of my ethnic mix would be interesting (paternal GP's immigrated from Ireland, would expect almost 100% Irish there). I would really like to find my Italian genetic relatives.
Based on what I perceive to be a small probability that my relatives are in a database, is there other benefits or processes that might come from my submitting DNA?
I would appreciate input from anyone with much greater knowledge than me! Thanks in advance for your help !
Debbie