It is a much much simpler modeling program to use than maya or 3dmax and best of all it is super easy to make changes. Some firms like us have been using sketchup for design developments and client concepts way before Google bought the company, and after that it became much a more popular and many other companies are willing to invest time and money to write good lighting and rendering programs for it.
Google bought the company as part of their ambitious plan to map the world in 3D, which aided in city planning and shadow studies in large cities.
