So if you look at AirBnB, one of its 'features' is that all of the renters and sellers are pre-vetted (and yes this doesn't always work but it keeps problem people in the system low). Look at the 'clear' system for pre-screening air travelers.
This sort of automated sleep spot is vulnerable to being trashed, so one solution is to create a signup process where the clients get some sort of identifying token, a key if you will, that allow them to use units.
The Sleepbox folks have a cool futuristic render but they don't seem to have an actual unit. That is a red flag for me but it only means that I won't invest in one until I see one actually 'in production.'
Resupply and restocking is a challenge too, but only if you want fast turn around and low employment costs. You can hire folks to turn over a unit when someone leaves and just be on site the whole time. Depending on occupancy rate and charges will determine if that is feasible.
So there are lots of variables but I don't see that there are any huge barriers to implementing this sort of scheme but I do wonder if there is a working business model in there somewhere.