Self-centeredness and selflessness, enhanced by the modern worls of (social) media - a good thing or not?

It depends. A good servant can turn into a bad master, as they say. And selfies can often serve as a merit of self-value. Depends on many factors, among them insecurity, vanity, pride, manipulation from media, your values (and your family values) and other ones.
The authoress dealss with these factors (often using her personal experience as a journalist) to remind us than one should verify the information, considerate the manipulation (including self-manipulation and the way we perceive ourselves) and to think and act selflessly. Selflessness shifts the limelight to others, which (done healthily and with love) can help us to deal qwith our messes and find the true joy.
Also the look of an experienced - and Catholic! - journalist (with work xperience for the secular media under her belt) is both incredible and very educative.