The definition of coordination is the ability to execute smooth, accurate, controlled motor responses.
As a swimmer, it's fine to take pride from your skill in the pool. But that doesn't mean you should underestimate the benefits of exercising out of the water. Dryland is a great tool to help you become a better athlete - both in and out of the pool. Not all teams focus on dryland, but all swimmers can benefit from incorporating it into their training schedule. In fact the impact dryland training has had on competitive swimming over the past forty years is evident.
Coordination and kinetic chain (the interrelated groups of body segments, connecting joints, and muscles working together to perform movements and the portion of the spine to which they connect) are important for overall athletic development. And improved coordination, including hand eye, have been shown to help create better balance, increase upper extremity motor control as well as faster, more accurate repetitive movements. In other words better and quicker swimmers.
It's also important to remember that the strength, coordination, and flexibility you develop through dryland won't just supplement your swim training; it will also make you a better athlete on land!