It's not the point. If the tram is faster than the car then so should be the bus equally so, providing it too has it's own lane to keep the playing field level. So no advantage to trams, as I said.
But if we wish to expand the issue; since giving both a lane to themselves merely makes the rest of the paying public endure worse traffic jams/delays, and the only reason either tram or bus is faster is this unfair advantage, it is an unreasonable thing to do anyway.
And it gets worse when taxis, motorcycles, bicycles, and everyone but the normal drivers are allowed to use them. Talk about authorities making a second class group of citizens and using them as a cash cow, whilst trying to manipulate them into having a lower quality of life. It's just wrong, and not what we pay those in authority for, to treat us that way.