Trams run along roads and thus decrease the road carrying capacity for motor vehicles. An elevated tram, monorail or otherwise, permits road traffic beneath without demanding more real estate for roads. Real estate in cities is rather costly and wider roads take away space that could contribute taxes to the community.

I am confused. "No need to break the tarmac to install" -- would you not have to break the tarmac to install the track supports?

"No need for elevated stations" --- the same as a standard tram or street car?

"Easy access" -- like the lifts built into some trams?

What is the advantage?

Tall trucks & buses might hit the overhead beam. And there'd be the risk of collisions between monorail trains and traffic.

PS: Each post would have to take up much more road space, because it would have to sweep out to the side and then back over the monorail at near ground level, not up in the air above the traffic.

One of the greatest advantages of an urban train system is that it can be either elevated or underground. This prevents it from obstructing surface traffic, reducing congestion and allowing faster commutes for everyone. It also makes it much safer as train/auto collisions are a big problem.