I don't have this update (Win7) but I don't download "Optional" updates - so that must be why
It was only "Optional" on my Windows 8.1 installation.
It was "Recommended"/"Important" on my Windows 7, and installed along with "Critical" updates in Windows Update.
It may currently be "Optional" for you, but I wouldn't depend on it staying that way. If you see it listed as "Optional" in your Windows Update, use the "hide" feature. (I assume you're using manual install for Windows updates rather than automatic).
It's no easy task to find KB3035583 in the list of installed updates.
Even if you click "Name" in your list of installed updates to sort them, they seem to be listed in separate sections.
If you have MS Office installed the way I do, there are a lot of separate sections to check.
I can't say I'll never use Windows 10, but I'm certainly not going to beta test it for Microsoft, especially if it means sacrificing a working operating system in the process. I have every reason to believe there will be games that won't work on Windows 10 that worked on Windows 8 and earlier, just as there were games that worked on Windows 7 but not on Windows 8, and games that worked on XP that don't work on Windows 7.
And I wouldn't use it without the capability to change the Start Menu back to the Windows 7/Vista version.
I hate those space-eating blocks of garbage-that-looks-like-ads hanging off the side of the menu that you see in pictures of Windows 10 and 8.1.