In some cases, it makes sense for some of these to be notifications that ping you. I want my phone to remind me if I need to leave right now to make my next meeting.
Finally, you can configure each individual card provider to be on or off so if you don't like a particular type of card, just don't use it.
I'm excited to see if they will provide an API for this. I would love to write custom card providers so that I can get ambient notifications of things happening in my world (e.g. the build is broken on an OSS project I run, a motion sensor in my house was triggered, etc.)