Your definition of an autopilot and mine are quite different. If I turn on a piece of equipment, and it follows all of the directional guidance coming from my GPS, including turns, holds, and approaches, and I never have to touch the controls while it's doing all of that, then in my book it's an autopilot. A 2-axis autopilot, but an autopilot nonetheless. Yes, more axis are better but, as you point out, how much do you really need/want to spend in a VFR light single?
On the current Robinson R44 pricesheet, a base R44 Raven II with no options is $489K and the HeliSAS is $47K.
I have to say that I would love one in my Clipper II. It sure would take the tedium out of even the shortest cross countries. I suspect I'm over-appreciating its autopilot functionality and under-appreciating its SAS functionality. I'd like to try flying a HeliSAS equipped ship in order to more fully appreciate it, but I'm not buying one myself!