The good points far outweigh the bad. The benefits of tandem cycling are the same as a single. Aside from the aforementioned calorie consumption, cycling will make your legs very strong, lean and muscular. It looks more like a map to the stars homes. With the ripples in each muscle looking much like the Hollywood Hills.
Cyclists have one of the highest aerobic capacities of any athlete.
This means they can take in more air, extract oxygen, produce energy and expel carbon dioxide better than just about anyone. This strengthens your entire cardiovascular system, increases your metabolism and makes you feel unstoppable. Cycling will make you sleep better also. Aside from desiring that Sunday afternoon nap, you'll sleep deeper at night. When your heart is more fit, it beats slower at rest due to its higher efficiency.