Last Friday I bought an iPad 2. I just forgot that it does not support Flash. So that's why I thought why is there no app for the iPad and iPhone. I know that the settlers online is still in beta, but maybe it's something in the future.
The advantages of it:
1: You can play whenever you want and anywhere you want.
2: The Settlers online will get more players.
I'm sure there are more benefits but for now I'm gone.
I think it's a good idea.