
Filming an arrest MAY prove useful.
Filming yourself getting a ticket for a minor infraction is useless.
Filming yourself getting a ticket for a minor infraction would be rather useless, if you weren't being wrongfully arrested simply for doing so.
Had the guy not been arrested, I would agree, filming it would be pretty useless, but you don't know that until the LEO decides to stretch his authoritative powers and make the wrongful arrest.
Was the fact that he was filming what upset the officer? Possibly. But it's his right to, and the officer didn't understand or respect that right.
The supreme court regularly upholds that it is the right of the people to record law enforcement.
Bottom line, at the end of the day, and by the time this thread is dead and long gone, it is the right of the citizens of the United States of America to record, photograph and document law enforcement and their actions. Whether or not you think it is useful, whether or not you think it has helped in any way or at all, whether you think it is misleading, it is every citizens right.