Watercraft paddles can be separated into two categories: those for use in low-angle, or high-angle paddling. Typical sea kayak paddles are built for low-angle paddling, where fatigue reduction is prioritized. These are often 200-220 cm long.
Whitewater paddles, on the other hand, are built for strong strokes, and often sport wide blades to better move water. These paddles are shorter, often in the 195-205 cm range. Most packrafters would be well suited with a whitewater paddle, though your packraft use will dictate your paddle choice.