You're right the profit of the bitcoin users will be lessen because 5% to 10% of the salaries of the bitcoin will be go to the hand if government. There is good and back effects of getting tax of government from the users, the good effects is they will use the money to build infrastractures like public hospitals, school, health center etc. but beside the good things there is always a bad, the bad effects is they will get the money and they use it to their own needs and leisure to fulfill their wants.