First there is the extreme example of businesses and bands that fill their pages with joke memes and fail videos. They get a lot of followers, a lot of engagement, and they can't sell a ticket or a widget to save their lives.
Then there are the more subtle cases of businesses and bands posting content related to their field or style, but really still promoting the work of others. There are bands that post videos from famous artists they admire. There are businesses that post inspiring videos from famous athletes or motivational speakers. It brings in big numbers and they think they will ride these coattails to a bigger audience for themselves. Then they post one of their own videos and the engagement is no different than before.
Everyone wants to find that shortcut to a large audience. But really you need to build your own audience. You need to find the people who are interested in who you are and what you do.