I noticed if you run a business, building a personal brand can be powerful (i.e I make awesome cakes and then people see them and come and buy them), however outside of that and being a public commentator, it's a bit pointless.
Or an actor. Or a politician. Or an athlete. Or a nonprofit. All of them benefit from strong social media game. AOC has much more political heft than say, Rashida Tlaib even though they're both freshman in Congress. AOC's 8x more followers on social media might have something to do with that.