That only applies to the upgrade system, right? I assume you should still be able to do a clean reformat and re-install Win 7 and your key should still work?
Anyway, I'm not touching Win 10 until they get rid of automatic updates not being preventable.
Yes, there were 2 options. The clean re-install was also available, I guess you lose all installed programs in that case. This way I only lost the ones I had installed with Windows 10. (broken links on the desktop) Anything before that was still there.