No. What you are you doing is correct. There is no need of creating new view for Ads as such. Please report back if you face any issue with ad display in the test mode. If enableTesting = true, you should always see an ad regardless of which country you are in.
We don't show ads all the time, that's why we hide the view. Would it better to create a view when ads are to be shown and then remove it completely when we don't want ads? Anyhow, we weren't on the UI thread when using the banner view. Haven't seen the error since that was fixed, so hopefully everything works as is should now. Might this have been the cause?