According to Gideon :

There is considerable debate about the benefits of shading, although
I feel that it is helpful for a few reasons:

1) Modest energy savings which could add up considerably
over years.
2) Apperance. A nice screen or planting looks better than
than the AC unit.

I'd also add in lifespan. In some cases, ie: bright hot sun
on plastic parts, shading it may give it a bit longer life.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.