Self-love, defined as "love of self" or "regard for one's own happiness or advantage", has been conceptualized both as a basic human necessity and as a moral flaw, akin to vanity and selfishness, synonymous with amour propre, conceitedness, egotism, narcissism, et al.

What do we call a self lover?

egocentric, egoistic. (also egoistical), egomaniacal, egotistic.

What is the use of self-love?

People who love themselves are less likely to suffer from anxiety or depression; self-love also paves the way to a positive mindset which is an essential ingredient for success in life and for mental wellbeing. Learning to love yourself also reduces stress, lessens procrastination and makes you more focused at work.