Marketing is particularly important for a nonprofit organization
Non Profit organizations usually need ways to market their cause to volunteers who would want to help and to donors that will give to their cause.
It is much harder for a nonprofit organization to gain an audience in the same ways that a business providing a product or service would.
Nonprofits do not get as much social media attention and do not typically benefit from advertising, so it is wise for nonprofits to save their time and money on those things and channel their energy into the best ways for them to be heard.
The purpose of nonprofit marketing is to have a way for nonprofits to market their causes in a way that encourages people to help, which could be a dramatically different way than a traditional business would be able to get attention.