Imagine you're in a kitchen and you see cabinets around, both low and high.
Why is it commonplace to have doors on all of those cabinets?
It seems a hindrance to have two extra steps (open and close) to access anything in those cabinets.
Well, there is one reason some people might use... saying that it makes the kitchen look nicer. So, that's the main trade-off... easier functionality vs (arguably) better looking.
One real reason to have doors on cabinets is if you purposely want to make it harder to get in, especially for small children and pets. Though, that's mainly just for the lower cabinets, not a reason for the top cabinets.
A better reason for doors on the higher cabinets is if you are in an earthquake zone and worry about things falling out.
Having said those reasons, what if I'm in an area without earthquakes, children, and pets and I care more about functionality than looks? Then, it seems that I don't need any doors hiding stuff from me and guests.
I'd love to hear any other thoughts.