Banana leaves are a food that is used widely in a number of different ways.

They are known to be decorative, waterproof, and flexible in their use.

They are used for cooking, wrapping and food-serving in a wide range of cuisines in tropical and subtropical areas.

These leaves are also used for decorative and symbolic purposes in numerous Hindu and Buddhist ceremonies.

Banana and palm leaves were historically the primary writing surfaces in many nations of South and Southeast Asia. (source)

So can guinea pigs eat banana leaf at all?

Banana wrap holds no nutritional benefit for them and so isn’t a food to purposely feed a guinea pig, but if they nibble a little of it they should be fine.