Electrolytes are important for the body as they are minerals that maintain the bodies water retention level as well as acid/alkaline balance.
Sports drinks are not just marketing gags, they contain useful electrolytes that need to be replenished during workouts.
Water is of course the most essential part of a healthy hydration cycle but supplementing with electrolyte drinks will replenish the body. So if you're working up quite a sweat, pick some up!