Unless the developer paid AG to put it there; otherwise, I really don't get why it is there. Why not Swords and Souls? It has higher rating and plays than CotLI. Swords and Souls is even newer than CotLI.
@siodala afaik it's more kinda charts, so paying, rating or plays allover has nothing to do with this section... otherwise games like Kingdom Rush would surely appear.
Think it's based on how often a game is played in a specific period (don't ask me about the length.. maybe a week?), so you see the most played games of the last period.