I guess this route should be quite long. Anyway, I feel that
this route is rather unique in terms of the duplication.
At the start, it follows 153 route to Kovan. However, it turns to
Boundary Rd and AMK Ave 1. So, this service provides a direct link
from Hougang Ctrl, Kovan to Boundary Rd and AMK Ave 1. Provides a
direct link from AMK Ave 1 to Shunfu estate and Thomson
areas.
Going on, it passes by Thomson Rd which 156 also passes by there if
we look at Boundary Rd. However, it provides a direct link from
Hougang, Kovan areas to Thomson Rd (MCYS and SLF Building). Provide
direct link to Novena and Newton areas too. After that, it follows
111 route from Orchard Boulevard onwards till Alexandra Rd. And
after that, it turns right to Queensway and goes to AYE via
Portsdown Rd. Please correct me if I am wrong here.
So it provides a direct link from Queensway, AYE to western parts
of Orchard and Novena, Newton areas.
It follows 197 route after that till Jurong East and runs almost
parallel with 198 to Boon Lay.
In summary, there is much uniqueness in this route as it provides
numerous direct links.
However, I guess that the number of fare stages for this route is
long seeing that it goes all the way to Orchard from Hougang and to
Queensway before going to Jurong East and Boon Lay. So, it actually
goes one big round at Queensway.
For demand, I leave that to the commuters to decide. 
