Function of Social Media Usage on Self-Esteem

In a recent journal article, a psychologist examines the relationship between social media usage and self-esteem. The author states:

'Numerous studies show a complex link between the time individuals spend on social media and their self-reported feelings of self-worth. While some users report heightened self-esteem through positive social interactions, others exhibit lower self-esteem due to constant comparisons or negative feedback. This duality raises questions about the moderating factors that influence whether social media benefits or harms an individual’s self-perception.'

In the context of the passage, what is the primary function of the statement about the complex link between social media and self-esteem?