Why?: The application only contains public marketing materials and does not require protection. Information that has already been made public, if compromised, would not cause severe damage to the organization. The value at risk is low so it doesn’t need to be encrypted.
However…you better be sure that only public information is available, and not any proprietary content, such as descriptions of future product capabilities. Again this all depends on what kind of data is being available as to how high the priority should be.