Research for music video: What is the function of a music video?

Music videos serve different beneficial purposes, which are to help boost the artist/band by promoting the song (single) which is taken from their album and also to produce visual pleasure for their audience. Most music videos are uploaded onto popular websites or shared on social music platforms, such as Youtube, Noisey and Vevo (big music channel on youtube), by doing this the music video can be watched from anywhere and as many times as desired, this is a great way to promote the artist/bands new and older music.
These music videos needs to sell the song so viewers can remember it, this can be done by having the visuals/narrative in the music video match to the song lyrics or focus more on the pure pleasure of entertaining the audience through the artist physical features (body or facial beauty) or their actual musical talent! Music videos don't make any money, it is a way to make the artist/band more known into the music industry, it will help them gain more fans which would lead to these fans purchasing their music and them making money. Below is one video that I think is a good example of a music video form:

Don Broco are an alternative rock band, this video isn't based off a story, it simple focuses on the bands musical abilities and doesn't focus on their physical appearance . Alternative rock is a genre of rock music that consists of vocals, guitar, drums and piano. It focuses on the artist and doesn't usually have a story/narrative. They use a lot of close ups which helps to establish each member's role, close ups of the lead singer, mid shots of the drummer or guitarist and then wide shots of the whole band performing. All of this is presented nicely in the music video by Don Broco (You Wanna Know), they have also taken a little bit of an artist approach by adding a soft pink backlight behind them which makes the video appear more aesthetically pleasing. The editing and camera movement  is in time with the music, the song is fast so the editing has to match up to the pace also at some points the song slows down, making the vocals the main focus and so the camera holds still and is focusing on the lead singer, who is also looking directly into the camera which breaks down the fourth wall. The members are also moving/ dancing when they perform, which makes the video more entertaining for viewers even though it is not in a choreographed way but more 'natural', as they are simply enjoying their music, this can also make viewers sing along to the song or even dance, which I think is the effect a good music video has on a viewer.