At All-Stars, players may elect to play in a stronger division than the lowest one they are eligible for. Rising Stars (U1100) may choose to play with the Bright Stars (1100-1399), and Bright Stars have the option to play with the Super Stars (1400+).*
If you are just below the cutoff for a higher-rated division, playing up would mean somewhat stronger competition (around 100 rating points on average), which a lot of players prefer. It also means longer time controls. Rising Stars will play five rounds at G/30 and will finish all their games by 3:30. Bright Stars will play five rounds at G/45 and will finish at 5:30 or 6:00. Super Stars will play G/75 but will only play three rounds and will finish at 5:30 or 6:00 like the Bright Stars. However, playing up would definitely make it harder to win your section.
*NOTE: If playing up would result in odd numbers of players in both affected divisions, then the move will not be allowed. Also, because the Super Stars division is only three rounds, requests to “play up” into the Super Stars section will be denied if adding another player to the section would result in an odd number of players in the Super Stars division.