Plastic Containers vs Stainless steel

Recently had a kitchen inspection, The inspector suggested to change from plastic ambro containers to stainless steel containers to store hot foods. Can somebody explain to me why, if you cool the food product down properly before going to the walk-in what's the difference?

The only reason I can see is that stainless steel holds the temp much better than plastic, so once the product is chilled is stays chilled and can get even chill down more since the metal conducts temps better. I use stainless and found out that the steel is easier to clean, it doesn't stain or hold in odors. Another reason for the switch might be that plastic is pourous and bateria and still hide out in these cracks in the plastic and WHAM cross contamination. This could be a costly switch since stainless is more expensive than plastic. Just make sure you switch because we don't want you to have to close down because of health violations.