Windows won't let you overwrite files "in use" and "file" is determined by the full pathname.

Linux will let you overwrite files "in use" (though the program(s) using them may not notice) and "file" is determined by a magic number, the inode - you can delete a file from a directory, really it's removing _that inode_, and put a new file in place with the same name, it's a _new_ inode. Programs that still have the file open are referring to the _old_ inode, which only goes away once everyone stops using it.

So actually you need to go round restarting your programs/services on Linux to get them to pick up changes (most package managers do that automatically), but at least it's _possible_ to make those changes without a reboot. Windows has to go into a special mode where nothing else runs, to be sure that it can update files.