I was trying to convert Office 2003 into a set of portable applications, and for that purpose I needed to do all of my updates at once if they were to be included in the portable executable package. Or you might be trying to install all available updates at once - that is, you might not be willing to wait around until the webpage did detect all of the updates you might need.

Or if you did go online, as I had sometimes experienced, that webpage might not be willing or able to detect the condition of your computer and figure out which updates you needed. Or you might not be able to go online when you were doing your installation. For instance, Microsoft might decide to cut off that source of automated updates for Office 2003, just as it had cut off its Office Updates automatic detector. But under various conditions, that would not work either. Microsoft was apparently still supporting Office 2003, and it was still possible to get updates from the general-purpose Microsoft Updates webpage. But that webpage was no longer available. You would just go to the Microsoft Office Updates webpage and let it take a look at your computer and tell you what you needed.

Once upon a time, that was easy to determine.

At one point, I had installed Microsoft Office Professional 2003, and I wanted to know what updates were available.

Microsoft office 2003 sp3