It's never that easy. You'd be surprised the number of homeless folks being in that situation because of things like addiction, mental health issues, etc. Just giving them the money is mostly not helpful.
Even if a percentage just burned through it on drugs, it definitely would be that easy for most of the situational homeless. It would also help to prevent others from falling down the addiction/mental health rabbit hole. Being homeless on the street is a highly stressful endeavor, that constant stress exacerbates the mental health issues, motivates drug use, etc.
Just handing over that money to people about to be homeless would do far more than paying administrators to badly run a shelter that homeless avoid because they get all their shit stolen regularly.
If today you give every homeless person in SF 50k, tomorrow we'll have even more homeless because tomorrow a new batch of homeless people will come to collect their 50k.