IIRC WoW just provided a layer to point 32bit binaries to 32bit libraries on 64bit systems.
So you have the ass-backwards situation where %WINDIR%\System32 is full of 64bit dlls, and %WINDIR\SysWOW64 is full of 32bit dlls.
So you have the ass-backwards situation where %WINDIR%\System32 is full of 64bit dlls, and %WINDIR\SysWOW64 is full of 32bit dlls.
WOW64 (in 64-bit Windows OSes) does 32-bit to 64-bit.
The naming of System32 made sense back when they came up with it, but now it's a bit ridiculous. However, since there are so many incompetent Windows programs using hard-coded paths instead of SHGetFolderPath (including, BTW, literally every Java desktop app that doesn't include its own shim-- the JVM itself has this bug!), it's something Microsoft doesn't have the ability to fix.