But there is single player mode, I would love to see a trainer for this game.
Being online only has two effects.
1. It makes it exceptionally difficult to make a trainer that works only in single player mode. Multiplayer cheating is not something Cheat Happens supports.
2. It makes changing stats difficult if they're stored online. This makes options very limited.
Diablo 3 was a very good example of always having an online connection destroying an opportunity to make a good trainer.