For applications where there may be limited exposure to moisture. Moisture resistant boards are usually (but not always) dyed green for identification purposes.
Moisture Resistant MDF behaves much the same to Standard MDF in terms of effortless machining and consistent surface quality. Where it differs from the more Standard product is that it is tested to be suitable in humid conditions where it can often be exposed to moisture and occasional wetting.
This makes the product ideal for applications where moisture can fluctuate such as in kitchens and bathrooms.