It may sound unexpected but the number of followers is not necessarily proportional to the level of engagement, I can tell you more, in many cases, micro-influencers have a higher level of engagement compared to celebrities with millions of followers.
Influencers provide a high level of engagement by interacting with their audience, asking them questions, reading and answering their comments. Social media influencers are more persuasive and more engaging than those influencers we see on TV: they are in contact with their audience 24/7.
But all this talk about the engagement was just a prelude. Customer engagement is important to marketers mostly because it's the basis of brand loyalty. In other words, the stronger emotional connection with a brand is built with the help of influencers, the better it is in terms of brand loyalty. And you know all you need to know about brand loyalty- it's the desire of customers to stick to the same product, recommend it to friends and family becoming a true brand evangelist and an advocate.