More supply is more supply. It'll probably drive rent down a bit, assuming the plan works. This makes little difference to unemployed homeless people and does nothing to address the fact that many wealthy people see homes as a tool to secure their capital, but it's not nothing. Hopefully it will help some people who are on the brink be a bit more secure in their housing.

Are they were they are needed? Would we need to move people across the county to fill them? Or are they kept mostly empty as a form of storing wealth?

Please don't provide this stat without context. It just promotes cynicism and despair. Reality is complex, and our solutions are going to have to be complex.

Many of these vacant homes are nowhere near major homeless populations. But office buildings often are.

https://ggwash.org/view/73234/vacant-houses-wont-solve-our-housing-crisis

Edit: If you prefer videos, here's a good one: https://www.youtube.com/watch?v=3xZXdXxYBGU

Greedy real estate hogs and speculators are criminals imo.