This question gets asked almost weekly. Here is one thread about it, I'm sure there are at least 4 others:
https://www.techspot.com/vb/topic106738.html
Its not even a real service pack if you compare it to prior service packs for Windows XP and Windows 2000. You can't slipstream it to a virgin 2001 XP disk. Its been covered 402342 times on these forums, and everyone that asks already knows that all it is is a ton of updates that have came out since SP2, but all in 1 package.
Bottom line is, if you want to install it on your SP2 install of XP then do it. If you don't, then fine, don't install it. I don't understand why this is such a big issue when to even ask the question you probably already know the answer.