Notifications get rolled up all the time, if I've received a lot of messages in Signal or Teams, I just have one notification in the dropdown for each group, even though I may have "received" 50 notifications from that group.

On emails, reply-chains are prevalent, so I can read the latest one and usually not have to open 20 emails.

I have some services set to email me events, transactions, and notifications, which I don't need today. However, sometimes these sites go offline, discontinue a product, remove the ability for you to view prior information or contributions, archive old data, change their ToS to something you can't stand, any number of things that might mean that data is now unreachable to you. So for those emails I just sort them off and they're archived.