Maybe I'm just a billy no-mates, but even with perfect accuracy the kind and volume of notifications I get on my phone just wouldn't really benefit from summarisation. Maybe for a group chat I haven't checked in a while, but outside that it's not like I've got people sending me essay-length messages.
Well, I'd say it's probably 'right' like 95% of the time where it conveys a good sense of the original intent/sentiment. But, that other 5% is what is "way too often" because in those instances it can be so far off that it could be classified as "not even wrong"....
My impressions are the exact opposite: it perfectly summarizes everything to the point like 98% of the time at least.