Ah but that is while it is free and presumably everyone else is using it. If it costs a dollar people would have to enter payment information all of a sudden, s

Ah but that is while it is free and presumably everyone else is using it. If it costs a dollar people would have to enter payment information all of a sudden, so it is putting a decision point in front of people where they have to expend effort and money (albeit a small amount of both) to keep using this thing. If their friends seem hesitant about it maybe they won't sign up to pay for it.