What is "Program Files (x86)" actully used for

What is "Program Files (x86)" actully used for

i was installing Sekien no Inganock ~What a Beautiful People~ Fullvoice
Reborn onto my computer last night, since learning about Symbolic links
i've created a Visual Novels Folder in Program Files, Visual Novels that i
had previously installed in their default locations have a symbolic link
in this folder and their organized properly (ie. all Lair Soft games go
into one folder, all Type-Moon gaesm go in another, Type Moon games are
broken into 2 groups, Fate and Tsukihime for the 2 different stories
(Fate/stay Night, Fate/Hollow Ataxia/Tsukihime, Melty Blood))
Sekien no Inganock ~What a Beautiful People~ was originally installed into
C:/Program Files (x86)/Liar/Sekien no Inganock
(i renamed the folder from the japanese text after the translation patch
was applied) so it got a Symbolic Link in
C:/Program Files/Visual Novels/Liar-Soft/~What a Beautiful~/Sekien no
Inganock ~What a Beautiful People~/Sekien no Inganock ~What a Beautiful
People~
i did the folder structure like that cause i was aware at the time of the
translation of the REBORN edition and was going to get it aswell, i went
to install it, natully the installer defaulted to Program Files (x86), i
changed the path to my new one however after it was installed the folder
didn't appear where i though it would and the icon was on the desktop
(indicating that it had been installed)
using the icon to go to where it had been installed and i found that it
had been installed into the path i specified yet the (x86) has been added,
despite the fact that i didn't add that
after uninstalling and this time using browse to click on the folder
(rather than type it out like i did) it did the same thing, rather than
installing into Program Files like i specified it installed it into
Program Files (x86), the rest of the path remain fine (so it clearly
wasn't getting the default file path)
i have installed Bazooka Cafe and Cavas 2, Bazooka Cafe wanted to be
installed into Program Files (x86) however i specified it into Program
Files and it installed fine and works like a charm (apart from crash at
the title menu cause by my friend's Censor Patch which she fixed up),
Cavas 2 just wanted to be installed into the root directory of C, i
changed the path to Program Files and it worked out fine
now the only thing i can think of is that Windows is forcing my Sekien no
Inganock REBORN installer to always install into Program Files (x86) when
i specify Program Files, so i am wondering, what is the exact purpose of
the 2 Program Files cause i always though that it was for compatibility
with older Installers that use %ProgramFiles% and 32-bit installer to
separate from 64-bit programs and it was solely just to make thing look
neater and that it wasn't an enforced thing