It keeps the air moist which prevents the veggies from drying out. Just like your fridges veggy drawer which traps moisture
Come and work in the north as a mechanic during winter tire season, and you can experience this all day.
I worked at a forge where they did this next to the presses in the summer, it was super nice. Less sexy than you'd imagine though.
This rots the vegetables. I turn the little nozzles off when I’m feeling ornery.
Why do they do it then?
It makes them look pretty and weigh more
It keeps the air moist which prevents the veggies from drying out. Just like your fridges veggy drawer which traps moisture