I would have agreed with you before using Roam research, but that opened my eyes a bit. I do suspect though that it is easier when thinking about a tool that is built more for personal use, rather than one built for collaboration.
There is something very natural of having dates be actual objects because they are an actual thing you experience. If you think about a character or a number, treating those as objects wouldn’t be quite the same. I wouldn’t want to just jot down some notes about the number 5, but it intuitively makes sense to jot down some notes about a date or period of dates (week, month, etc).
Now, in Fibery you could build something similar in utility, but it can’t really be done without having to actually think about Types. Without dates being actual objects, you are forced to maintain some kind of view that shows all things associated with a date. However, you would need to keep that view up to date for each new Type you add and you can’t just add some notes to a date without having a notes Type.
To speak to Fibery’s flexibility, I have been able to create my own Dates app in Fibery though. I can just add dates, months, quarters, etc with auto-linking between them to have objects for what I care about. I can also auto-link them to other Types based on the date fields applied to them. I think if we ever have polymorphic relations with auto-linking, then it could clean it up a bit.