This behavior can be explained by several reasons.
First of all – instincts.
Here we must remember the wild ancestors of domestic cats, who covered their eyes while eating so that their visual organ would not be damaged by the bones of their prey or by flies that were attracted by the smell of meat.
This is the skill that pets have adopted from their ancestors.
Nowadays, a pet may cover their eyes if the edges of the bowl are too close to their eyes, which means that they are trying not to injure themselves.
The second reason is trust and peace of mind.
The thing is, a cat closes its eyes when it enjoys tasty food.
It also means that the animal feels safe and that no one will hurt it or take away its food.
Most often, this behavior can be observed when the cat loves its owner, they have established a trusting relationship, and there are no other animals or small children in the house.
