One reason these size shelters, or tents, are not more commonly used is because they're too small resulting in predictable and counterintuitive negative outcomes for the people that rely on them.

1) they don't have enough space for multiple occupants plus all of their belongings. Secure storage is a real challenge for people experiencing homelessness.

2) environments of isolation are bad for mental health in general but also increase the chances of overdose for drug users.

Ultimately the source for homelessness and drug addiction is systematic poverty.

As interesting as shelters like this are, they are far from anything resembling an actual solution. Plus they're likely are not the cost-effective or carbon-friendly options, despite having a solar panel glued to it.