Buying subscribers is one of the ways of fast monetization(monétisation rapide). YouTube makes it mandatory for you to have 1,000 subscribers before they’ll even look at your channel for monetization. If you have great content but subscribers aren’t letting you move forward, buying subscribers gives you the boost you need to keep going.
For example, if individuals pass by an empty restaurant, they don’t wish to enter. But if they notice it is full of individuals, they will want to join as well. The same applies to YouTube. If your audience notices that your channel is full of subscribers, they will be more inclined to watch your videos, subscribe by themselves, and distribute your videos.
With the right number of subscribers, you can join the YouTube Partner Program. Once you are accepted, you can start earning from advertisements and even partner with brands that want to sponsor their products in your videos.