Answer:
1. Most of it is because of publicity, they want to gain more followers,friends etc etc. Since most of social media users want popularity so that many people will notice their posts, pictures, and many more.
2. Your privacy might be at risk since you are giving up your privacy for popularity. Hackers, haters etc etc might still your data. They can blackmail you, example:they are asking for money or they'll post something that violates your privacy, Some people might send you threats.
3. Setting up safety measures specially to your social media accounts. Nothing good will come out if you want to gain popularity except if you're gaining money from it but make sure you are not violating any laws.