Here is the definition of a SPORT:
Sport is an activity that is governed by a set of rules or customs and often engaged in competitively. Sports commonly refer to activities where the physical capabilities of the competitor are the sole or primary determiner of the outcome (winning or losing), but the term is also used to include activities such as mind sports and motor sports where mental acuity or equipment quality are major factors.
Here is the definition of a HOBBY:
Hobbies are practiced for interest and enjoyment, rather than financial reward. Examples include collecting, creative and artistic pursuits, making, tinkering, sports and adult education. Engaging in a hobby can lead to acquiring substantial skill, knowledge, and experience. However, personal fulfillment is the aim.
So it is a hobby/sport, sport/hobby, hobby or sport. Whatever it is called it is fun (and profitable).
And don't forget ADDICTION:
An addiction is a recurring compulsion by an individual to engage in some specific activity, despite harmful consequences to the individual's health, mental state or social life. The term is often reserved for drug addictions but it is sometimes applied to other compulsions, such as problem gambling, and compulsive overeating. Factors that have been suggested as causes of addiction include genetic, biological/pharmacological and social factors.