My folders also look like yours. Here's a scenario.... If you export an image, say to email to someone, and then they come back to you wanting a larger copy, you only have the filename to go on. If that filename contains the date, then it's an easier task to directly go to the correct folder. I only keep recent photos on my computer, so I may end up having to search several drives to find the original if it didn't contain the date in the filename.
I came upon a couple of issues with filenames - one was that I went round my camera numbering system (10K photos) and this confused my LR catalog. I can't quite remember now, but I think it was that it won't allow two photographs to have the same name, even though they are in different date folders - but I may be wrong.
The other issue I came across was that I was using two cameras, as was my friend, and we wanted to put all of the photos together into one folder in chronological order. I came up with the idea of reverse date and time stamping them. This was after us both syncing the time on all our cameras.
Finally, not sure if this is what you were after - I set it up as a Lightroom import preset using 'custom'. If time isn't important, sometimes I just use date, so I have two import presets depending on which I want to use.