It can help, but other degrees also have content writing value. For instance, the ability to synthesize and relate complex information is key to content writing, but can also be acquired from studies in education or philosophy. Companies that offer content writing positions tend to find it easier to train someone in a complex topic than to train someone to write, however. For example, as a healthcare professional with mediocre writing skills, you're less likely to be hired as a healthcare content writer than a strong writer with no healthcare background (but who can be trained in healthcare topics).
Lack of creative license. Though you may think content writing will give you a chance to showcase your creativity and rousing ability with words, in fact, most content writing is seen as a way to sell a product or simply inform a reader of the facts. In a content writer role, you will likely be writing about dry or dull topics, though you may get a chance to also write copy for more engaging projects on occasion. Your employer will dictate the topics you write about, and you will need to learn to be flexible and engaged on even the most obscure or boring subjects, regardless of your personal preference.