A jersey with no rear pockets is unusual for regular cycling. The classic three-pocket layout is standard for a reason—it lets you carry food, tools, your phone, and other essentials on your back where they're easy to reach while riding. Most cyclists rely heavily on those pockets, so going without them is a real limitation.
That said, there are a few scenarios where a pocket-free design makes sense. Triathlon tops often skip rear pockets because athletes access nutrition from the front during a race, and pockets would be uncomfortable in the aero position. Some casual lifestyle jerseys also skip pockets for a cleaner look if you're just cruising around town.
If you're doing regular road rides, gravel adventures, or anything over 30 minutes, you'll almost certainly want pockets. Without them, you'd need to rely on a frame bag or saddle bag—less convenient for grabbing a snack or your phone mid-ride.