We do but call it what you will, we're clearly asking for a feature here, and being able to see most of our 'working notes', while automatically hiding from that list old, outdated, or irrelevant notes. I can't achieve this through tagging, and I don't think there are saved search options in the left list are there?
I expect better empathy from a product owner, frankly, rather than just a criticism of naming. You're clearly missing a feature here based on the number of people asking for things like it (including notebook searching).