No, by accepting the Terms and Conditions, Cubase users agree to use only 4/4.
While the program does give a superficial appearance of allowing other time signatures, this does NOT imply that Steinberg actually condones such practice. For instance, the metronome and grid lines have been specifically designed to discourage compound time, and a little-known feature of Cubase is its ability to give a painful electric shock to anyone who persists in attempting to use anything but 4/4.
The metronome in (the by-then-tablet-only) C12 will just be a synthesised voice shouting ONE TWO THREE FOUR, but that’ll be OK because the only people who’ll still buy the (new toy-style, touch-only) Cubase will have no idea that other time signatures are possible. Happy little people. See them smiling. The Cubase screen it pretty and they can touch it.
See the pretty screen. Touch the pretty screen. Life is good. One two three four, one two three four, one two three four, …