Nvidia says two ways to install drivers

I've noticed that on Nvidia's site, in two different places they recommend
two different ways to install detonators, one on the driver download page,
and the other on their support/faq's page. I've pasted both in below. I
realize that you can just execute the file these days, but can someone tell
me why Nvidia tells you to just execute the file in one place, then tells
you you have to uninstall the old driver first before you execute the file
in another place.
Here they are...the two opposing suggestions. WHY?

On the Nvidia driver download page for 52.16 ;
"Before installing new drivers make sure you uninstall all NVIDIA display
drivers from the Windows Control Panel. Browse to the Start Menu Windows
Control Panel Add/Remove Programs and search for "NVIDIA Windows Display
Drivers" or "NVIDIA Display Drivers" and select remove".

Now from the Nvidia support/faq's page;
""The NVIDIA Detonator drivers are self-installing drivers. This makes it
very easy for end-users to upgrade their drivers to the latest version.
Simply download the appropriate drivers from the NVIDIA Web site at
www.nvidia.com, and save the file to your hard drive. Make sure you are not
running any download utilities in the background. This tends to corrupt the
drivers if not disabled.Once the file is on your hard drive, disable any
anti-virus programs running in the background. Certain anti-virus programs
will prevent you from making any changes to your system files and can
corrupt your drivers. Once you have prepared your system for the driver
installation, simply run the drivers you have downloaded by double-clicking
on the file. The drivers will automatically update your current drivers and
make the necessary changes to your system. If you are running Windows NT4,
it will ask you which graphics card you are installing. This is because
Windows NT4 cannot correctly detect your graphics card make and model. Once
the drivers have been installed, Windows will ask you to restart your
computer to complete the changes. Allow Windows to restart. Once you are
back in Windows, you are done with the driver installation.

These two suggested ways to install Nvidia drivers are clearly different.
One says you have to uninstall the old driver, the other says to just
execute over the old one. WHY?
It's just confusing to a lot of people......me included :-))
Thanks
DH