Curved shaft poles are designed specifically for speed discipline racing—giant slalom, super-G, and downhill—where you spend a lot of time in a low tuck position at high speeds. The bend wraps the poles closer to your body, reducing aerodynamic drag so you can carry more speed. If you're not competing in those disciplines, curved poles offer no real advantage.
For the vast majority of skiers—including all-mountain, freestyle, backcountry, and recreational riders—straight poles are the way to go. They're easier to plant and maneuver, and they cost less. Even slalom racers use straight poles because their discipline involves quick, frequent pole plants rather than sustained tucks.
A common mistake is assuming curved poles are an upgrade because they're pricier, but they're actually a specialized tool for a specific job. Unless you're racing speed events, stick with straight shafts.