I didn't even notice there were notifications until I'd played many games and never use them because they're way too spammy with pointless info.
IMO it would be ideal if you could filter them to drop it to just critical events, which has been suggested before (the idea of filtering options, that is).
Also agree that a clear all button would be nice.
The new notification system is an ok idea but it's like it's not a fully thought out or fully implemented idea. Needs filters and needs a clear all button.