Housing units is what matters for solving homelessness, not number of people housed. These tiny homes aren't intended to house whole families. Yes, you could fit 8 to 10 unrelated homeless people in a single family home or townhome, but there's a reason why that's not pushed forward as a solution—people don't generally want 9 strangers as roommates.
I definitely agree that the economies of scale that come with the shared walls make a huge difference for general practicality, but I was only speaking of land use per housing unit.
Edit: Here's a link to the satellite image [0] so you can see the depth of the property. The unit alone is about twice as deep as it is wide, and then it has a backyard per unit in addition to that. My very rough estimate with the Google maps ruler suggests about 1000 sqft footprint per unit.