Interesting. Except for the support of new hardware, any other reason to upgrade? I helped a guy with Win 8, then 8.1 update, years ago. I couldn't stand the interface and had to learn a bunch of "secret" commands (Windows-X?) to call up the Start Menu and other items that Microsoft thought I shouldn't know about.
And, as far as new software support, it's my understanding that Win8 does NOT support h.265 natively. (Whereas Win10 does.)
Also, considering the installed base of Win7, I figure there's a better chance of White Hats finding bugs in Win7 than Win8.
I won't be updating my hardware, so I don't need to update OS. And even if I did, I would put up with learning Linux before letting Micrsoft take over my computer with Win10. IIRC, Win8 also wanted to phone home during install and you had to know to chose "Local Account" during setup.