Low poly game art, trends, and exemplary games

How does low poly work and why it is preferred for mobile?

At 0.25 you see least number of objects resulting in fewer vertices, draw calls and triangles. However, the graph shoots up at 0.29-0.30. This is resulting from rendering a lot of elements (trees and the houses) at once. As a game maker your job is to keep this as low as possible. While LODs are a great thing, it cannot outdo a properly thought-out sequence.

Trends:

Subway Surfer:

Manuganu:

Gunship Battle: