It might be that the future of sticky notes is Quick Notes as in iOS 15, but they do different things, I agree. Apple really should integrate the concept of sticky notes into both Notes and Reminders, to create a bit of a hybrid - a sticky note that can act as a reminder, etc. Even better would be sticky notes that reveal themselves when using certain macOS or iOS modes, so that when I’m at work I see my work stickies, and when I’m at home I could see some home stickies, etc. It should also be easy to remove a sticky by converting it permanently to a note or reminder, or maybe even a calendar event or contact.

Ah, the problem may just be that I've never explored their full features. I think of them as those little square text notes you can put on the screen, and have never tried to do more with them. Given that understanding, I don't see how they'd map well to Notes, but if there are other ways to display or interact with them that I wasn't aware of, then maybe it does make sense.