It’s to let people know you’ve moved on if they are looking for you. Also to rub it in the face of your former colleagues and managers that your now at IQVIA instead of their dumb company and they should be jealous. The promotion piece is the same. I’m doing great here, ha ha former employers, oh, and I’m good, so think of me if you have an even better job elsewhere.
So that your network & recruiters know you have a higher position now.
If you work hard and earn a promotion why would you not be proud to share that on a social media designed for professional connections to keep up with your career? It’s okay to be happy/proud when you earn a promo and share it with others
It keeps you top of mind in your network. Also humble brag to people who doubted you along the way.
Show off, bragging, self-satisfaction
Don’t judge, it’s important to create your personal brand these days, no one gives a shit anymore if you work at google or any other big tech. Bragging on LinkedIn opens up a lot of opportunities to do side hustles, like earning from the digital platforms, increase your visibility among people, etc.
It happens automatically when you update your profile unless you opt out. Most people aren’t showing off, they’re simply keeping their profile updated and using the canned announcement. The custom promotion announcements are pretty cringe but I don’t see anything wrong with celebrating career milestones.
Bragging rights.