The people who often practice piano in the circle of friends are music lovers and professional musicians.

1. Music lovers: These people love music, like to play musical instruments, and have a high pursuit of piano skills. They often share their practice results in their circle of friends to show off their musical talents.

2. Professional musicians: These people are professional musicians. They need to constantly practice their piano skills to improve their performance. The practice videos they share in their circle of friends may be to show off their abilities to their fans, or they may be to find more performance opportunities.