Because by agreement it can make people more trustworthy in putting their assets in bitcoin and it can make or have a good impact on bitcoin prices and also smoothness in trading or in transactions in the purchase of goods and services.
If bitcoin is legit in your country many people's are interested to join in investing in bitcoin cause they have trust to putting there money in bitcoin for investment. They know investing in bitcoin they gain good profit, and they can easily to transact like trading or purchasing of goods and services.