Both airsoft and paintball are both hobbies based on replica firearms and war games. Is this unhealthy? That depends more on the person themselves rather than the hobby. An interest in pursuing a hobby that involves weaponry only becomes unhealthy if taken to extremes - which are true of most things in life. Paintball and airsoft are not morbid hobbies and only run the risk of being dangerous when participated in by dangerous people.
Paintball itself is a more mobile sport. It requires a certain level of physical fitness, mobility and skill - if you paintball then you gotta be able to move fast. The weapons themselves are functional and are only designed to serve the purpose of the sport as opposed to looking good. Paintball rifles are designed to take a real beating when it comes to their use. Paintball fans fall into the 'extreme sport' category and enjoy the pure adrenaline of each paintball match and are driven by the desire to win.
Airsoft is a somewhat different sport. The guns used in airsoft are both conversation pieces and are also functional sports 'weapons'. Airsoft rifles and pistols are capable of firing both small plastic pellets and paint filled pellets so are useful both in the sport itself and also for backyard target practice.
The major difference is the power of the guns themselves. Paintball guns are driven by high powered gas cylinders whereas airsoft guns fire projectiles either through springs, electronic firing mechanisms or with compressed gas. The issue is that most airsoft guns lack the range and accuracy of the larger paintball guns simply because they were never designed with long range fire in mind.
Conversely airsoft guns are available in a huge range of styles and models. Everything from a Glock handgun to a sniper rifle to a CAR15 assault rifle. Airsoft guns are equally at home hanging in your livingroom or at use on the airsoft playing field. You can even go as far as buying an airsoft minigun. Many airsoft fans simply collect the guns and never get involved in airsoft war games at all. This is the much the same as many sword collectors - they display the weapons at home but don't go running around waving them at people.
The truth is that neither airsoft nor paintball is superior. They're both a case of personal preference. If you're the extreme sports type then paintball will suit you more. If you're more of a collector then airsoft will be more you thing.
Regardless of whether you're a paintball fan or an airsoft fan it's essential to take proper safety precautions when using these guns. Proper eye protection in the form of safety goggles should always be worn and suitable protective clothing to cover your neck and upper torso should also be worn. Even though some people see these as guns airsoft as toys they are capable of causing paintball injury either through accident or even deliberate malice.