As Bonnie pointed out on another thread table adapters are merely a wrapper for the data adapter and thus tightly coupled your data table to your data store. The dataset is dumb. It does not care where or who the data store is. If you plan on porting your app or growing in anyway now you get to rewrite more data access code that if you used a generic dataset for your memory storage.

To each his own, but table adapters should be for simple and very small access tasks.