In a restaurant or in any commercial kitchen it is obviously important to keep the work areas clean, tidy and disinfected.
Nobody would like to have guests who got sick due to the unhygienic circumstances.
The ventilation is often a part of a kitchen which is thought to be not so important.
The extraction hood above the appliances leads to fans and the extracted vapor grease and fat flows thru these.
This is how it looks like on the inside without maintenance. It’s covered with fat extracted thru the hood.
This can shorten its lifetime and can cause damage to it which leads to expensive repairs.
Maintenance is always cheaper than repair.