It depends on how you ride. A jersey without a hem gripper can work fine for casual spins, coffee rides, or commuting at a relaxed pace where you're not leaning far forward or stuffing your pockets. Many lifestyle and relaxed-fit jerseys skip the gripper for a softer, less restrictive feel around the waist.
The downside shows up when you load those rear pockets with a spare tube, snacks, or a jacket. Without a gripper strip holding the hem in place, that weight pulls the jersey up—exposing your lower back and letting pockets sag. The more you ride in a forward position, the more noticeable this becomes.
If you're doing longer rides, carrying gear, or just hate tugging your jersey back down every few minutes, you'll want that silicone strip. Save the no-gripper option for short, easy rides where comfort matters more than performance.