Note: I've been homeless twice. Both times I wanted to get out of it my step A has literally been "find lowest cost of living place in the country with low unemployment and work in day-labor agencies until I have enough for rent." It's worked both times, and relatively straightforward. It would not have worked in SF.
You could get a lot of the (arguable) benefits with less transportation costs and a whole lot fewer political/legal problems by doing it in, say, Merced County.
SF does have a program that will help you travel back to Family in other states/cities, but I don't think they can just ship people to a lower cost location
Added bonus, those who are capable of getting back on their feet can actually afford to live there afterwards instead of endlessly cycling through welfare cliffs.
Not spending the money needed to house and treat people.
Remember there is finite money and there are hard decisions about whether to spend some money on say a homeless adult person that has been given many chances vs a young child who may be even more influenceable with the same amount of money. In many case these taxes are coming from families who no longer have the choice to spend that money on their young child or own family members.
Given infinite resources it may be worth it, but at the cost of robbing say a young child of these resources or multiple life-times of labor it may not.
Homeless people aren't helpless animals in need of coddling. They are human beings with intelligence, perfectly capable of exploiting incentives and your kindness.
They terrorize eachother, and those who interact with them.
It only takes attempting to help a homeless person 2-3 times in person to see and understand that.
Needle exchanges, supervised injection sites, and cash stipends to addicts are going to be looked back on as hideously poor policy, and their supporters have blood on their hands.