This may vary by person. For myself, I'm quite disappointed that my geneological tree runs dry just a few generations back. I'd love to see where it, it being me I suppose, began - but it's simply not possible. But today we're creating what may be a record that, at least ideally, people even thousands of years from now will be able to view. Imagine being able to see the thoughts and 'writings' (in a manner of speaking) of your ancestor from thousands of years past - see the lands that they knew as home (or at least what became of them), and ideally even see their final resting spot. Perhaps this does not appeal to you, but I find it extremely intriguing. I mean these people are quite literally a large part of you. I find it interesting to just ponder on such things.

It has little to do with grieving or even remembrance. In my case it's mostly curiosity. In a way it's akin to visiting a museum of you. And in the future people will be able to do this. This gets even more interesting once you consider that at some point, perhaps not far from now, there is an extremely high chance that your descendants will reside on another planet. I see no reason to believe that these descendants would have any less curiosity about their heritage.

That playground will eventually give way to some apartment complex, road, or place to buy crap and nobody will ever know or care that it was there. But the people of today are what will make up the people of thousands of years from now. And that lingering connection and curiosity of the past is something that I expect will probably remain with our species (and even the species we diverge onto in the future) indefinitely.