I also don't see the point in people putting no estimated date of birth or area (obviously when the relation is still living that makes a difference) but how the hell are you supposed to know wether a name might link to yours if you don't have a clue where they come from?
I must admit, some of my "lesser" members of the tree also appear as "not known". However, I am remedying this as I go along. The reason is that I didn't enter a date of birth in my "tree programme" as I only have a date of baptism, so I entered this with location in the relevant place. When the Gedcom exported this, there was obviously not DoB or PoB, as these are in the christening info , which is not generally available to view.
Needless to say, I have also corrected this in my tree.
Another thing that gets on my nerves from time to time is the location. The spelling is atrocious, some people put things like "Wales, England", some use the old counties, some the new, some none at all, some put in the road and house number, so looking for one family in one place involves searching several variations of the one place. I wish GC would introduce a convention that most people could then stick to.
That would save time online and nerves.
