I agree that it should work that way, but I'm not sure it actually does. I have SUPER_SIMPLE set to 1, and a flight mode for Stabilize + Simple checkbox. I don't believe it actually results in SUPER_SIMPLE mode. I need to experiment more to see if it's using straight Stabilize or a form of Simple, but I don't think it's in the circle-the-operator mode like it should.
Really, this particular aspect seems far more complicated than it needs to be. We have a modifier on top of a modifier on top of a flight mode.
I think the intention is that any flight mode (loiter, alt hold) could be 'simple mode' (care-free yaw), and THEN if you prefer to have operator-centric directions (polar coordintes) on top of that, you can trade them all in for that mode. There might be an easier way to represent all this.
I went out to try Super Simple Mode on the Y6 and had a spooky experience.. one whole arm came to a standstill (both motors) and it tumbled out of the sky before I switched to (normal) Stabilize and recovered it. I have no idea what triggered that, but I was horsing it around tossing it left and right. I'll see if I can find the moment in the datalogs. This ship has been 100% predictable and stable otherwise.
I was trying simple and super simple yesterday. I had all my flight modes set to non-simple, ch7 set to enable simple and ch8 set to enable supersimple. Simple was working ok, but supersimple was having no effect and behaved just like simple mode.
You can check in the dataflash logs if it is being enabled by looking for the EV rows. According to  and  you should see EV numbers of 26, 27 and 28. In my logs I see 26 (simple on) and 27 (simple off) but never a 28 (super simple on).