Long work is spending a 12 hour working day filling in forms. Hard work is having an insight that pulls multiple an seemingly disparate ideas into one idea that ultimately helps the client improve their product.
Long work is always required. But hard work is scary. You might fail, something that you cannot do with long work (assuming you can fill in forms). So long work sets the stage, because you show up and you practice and you learn. Only after the long work can you be ready for the hard work. And you only get the benefits from the hard work if you are willing to think differently.