As I’ve seen that this update is for people running (a 32 bit application on a) 64 bit systems, I’m wondering if there’s any value for me the optional KB2999226 update on my 32 bit system.
Optional updates A) aren’t compulsory and B) they usually say what they are for as these are normally for software that you have installed.
That KB isn’t just for Vista, it is also there for my win7 system. Did you not click on the More Information or Support information for that KB as that could give an idea what it is for and if it is necessary. You have to use the information that is to hand (or search) find the information to be able to make an informed decision.
As can be seen on the Google search linked to above, the only relevant result when searching this question in Google is the link to this thread itself, other than that there’s nothing.