So you still need their HW, not that useful.

Source on this? A quick google search didn't turn up anything

It's right there in the macOS EULA http://images.apple.com/legal/sla/docs/macOS1012.pdf, Section 2.B.(iii):

"[...] you are granted a limited, non- transferable, non-exclusive license: [...] (iii) to install, use and run up to two (2) additional copies or instances of the Apple Software within virtual operating system environments on each Mac Computer you own or control that is already running the Apple Software, for purposes of: (a) software development; (b) testing during software development; (c) using macOS Server; or (d) personal, non-commercial use."

This section was first introduced in the EULA for OS X 10.7.

Look in the marketing for any of the VM vendors (I installed 10.12 in Parallels a couple of days ago)