[citizenparker]

Many games have incorporated a feature to where you can try the game, and then have the option to give them money.

This is called a demo.

[Tichy]

Sure, but a demo is not very convenient (download, install, test, uninstall, download full game, install...). I guess they want to get people to buy who were so far not prepared to buy, so a low barrier to entry might be good.