What kind of balcony is this?

I came across this in Bangkok:

I kept wondering, why would people build a door that leads to no where, on the first floor? The roof of the lower unit is just made of thin aluminum. From the look, I can tell it definitely cannot support human weight.

So, why have that door? And they are all opened. Yes, I used ‘they’, coz the whole stretch of the wooden shop lots are like that! Interesting…