It is a helpful program. With minimal paperwork, you get a device with calling and data service. The phone hardware ranges from basic to decent. They typically have much less crapware installed than your average store phone.

Several challenges with the program exist, compared to payphones.

a) It is difficult to hold on to anything when you live on the street, even without any bad habits. Without a place to keep your things, they regularly get lost, stolen, etc. If you have a habit, you may also be tempted to pawn the device for a few bucks.

b) The paperwork and process is minimal, but is still a barrier. For example, some programs do not give you a device on the spot, but it must be mailed to you. I had mine mailed to a post office and it got lost. I never received the device, but I was marked as having ordered one in the system. From that point on, even years later, I could never qualify for another one.

Compare this to a stationary device that's always there that doesn't have to be maintained by you, and the advantages are clear.

New York has a pretty good system of LinkNYC kiosks, which provide basic calling service, and are maintained reasonably well (about half work at any given time.) They were better when they allowed browsing the web, but that functionality was taken away after Reddit raised a stink about someone browsing porn on them.